Carrying on. I think what I'm really picking at here is what people are and have looked for in things that resemble formal portraiture.
From time immemorial, people have commissioned painted portraits, and they still do. It was, and remains, a act that carries a couple of meanings. On the one hand, it's a projection of wealth and power, and on the other hand it preserves a likeness of the subject. The subject demonstrates wealth, and has a shot at a kind of immortality, if you will. Poor people never had a likeness made of themselves, of any sort.
Fast forward to the 19th century. There's an explosion of portraiture with the advent of the photograph. Even though the various processes were tedious and in modern terms expensive, the ability to have a likeness made became accessible to the middle class, and then even the relatively poor. While it may have maintained a thin veneer of social status "Oh, what a lovely quarter-plate tintype. You know, I had a half-plate done." it mainly shed that aspect of wealth projection.
Of course, we still have even today the social status, but it's landed on a handful of practitioners. Getting shot by Snowdon or Leibovitz would certainly be a social feather in the cap, as well as an obvious "tell" of wealth and power. As a general phenomenon, though, general portraiture shed that in the Victorian era.
The purpose in the Victorian era seems largely to be simply creating and possessing a likeness of the subject. As commenter remarked on the previous, on the memento mori photos of this era in which the dead are photographed with the living. If the point here is not a shot at immortality in some sense, I cannot imagine what is. The point here is to preserve a likeness, to remember the subject's appearance. Sally Mann had some interesting remarks on memory and photographs which might be a sort of salient side note here, the bit where photographs destroy memory.
This is, as near as I can tell, roughly the state of affairs through the 20th century. People go to "get their pictures done" with gradually decreasing enthusiasm for the next 100 years or so. More and more people are taking snapshots, but the results can be a bit unsatisfactory, there are no guarantees because you're an amateur using film and, let's be honest, not everyone is that in to it. Still, vernacular photography arises, and people get used to the idea that "lots of pictures of the kids" isn't a weird thing, or reserved to the wealthy, or any of that.
Enter digital. Everyone's a photographer now. There isn't any cachet whatsoever left having a photograph made of you, it happens more or less constantly. There's no rational reason to look for more likenesses of anyone. If we want to remember what so-and-so looks, or looked, like, we can just hop on Facebook or Instagram and see 100s of pictures.
The forces that drove the Medici to have their paintings made have vanished completely, except, one supposes, for inertia.
At the present time people taking pictures for money are all having a rough time, you have to find some angle to make it work. The standard line appears to be something about "quality" with some vague handwaving about equipment, experience, and passion. That doesn't actually work very well, but there are some things that have some traction.
By tying this portraiture business to specific times of life, to events, you can brings in some customers. "Seniors! Get your pictures done! Preserve the memory!" "Engagement Sessions" and so on. Almost any sort of specific reason, beyond "get your picture taken", will pull in some customers.
That said, standard portraiture is a thing you can still buy.
Let's interview me, I'm right here after all.
You could pay me to go down to one of the local studios, but my hourly rate is still north of a couple hundred bucks.
But I'd sit for Kirk Tuck in an instant, and if it wasn't tremendously inconvenient to get to his studio, I'd probably have pestered him to shoot me already.
The difference, for me, is that the shoot at the local studio is likely to be an itchy, boring, experience in which I stand in front of a mottled colored backdrop from the last century while some perfectly nice but dull fellow fusses with lights and waits for me to put on my Camera Face so he can shoot. The experience with Tuck would involve tea, conversation, and mostly no mottled backdrops. It would be interesting, because Tuck is an interesting guy, and because he knows that the pictures aren't going to be any good unless he makes it interesting.
The result would be in some sense just another likeness of me, of which the world already has an excess. It would be, if we had the wind at our backs, also insightful and in some way revealing, it would be in some sense beautiful, and the memory of making it would be of an enjoyable collaboration. Not itchy at all.
Also, I am a weirdo, so this sort of thing appeals to me even though as an introvert I find it exhausting.
As for events, I have one (1) photograph from my actual wedding, which I like a lot. It is an artifice of sorts, in that we all piled together into a sort of Last Supper arrangement for a Group Photo. It is also a real moment, because there we were at the wedding, just married. The photograph serves to evoke the memory of that terrifying day when my life changed and became what it is now. I'm glad I have that picture, but I don't need any more. (more were taken, that's the one we chose to print and hang)
So there has been, socially, a pivot. We're no longer getting from our portraits anything of what the Medicis' got. What we're getting now is much more tied to events, to times and moments in life. To be fair, there is a genre of painting which we might loosely characterize as "The Duchess McStuffing On The Occasion Of" which was likewise tied to events, way back in the day, but I dare to speculate that it wasn't the Main Thing driving painted portraits.
Now it is. There's an entire genre of retail photography with all the itchy posing weirdness of a painting (albeit on a somewhat shorter time scale) that is intended to evoke specific memories of a specific time -- which often isn't the time the picture was taken.
At this point we have this curious phenomenon where, a great deal of the time, the role of the professional photographer is to direct the subjects through a sort of play, which is then recorded by the camera. It's a sort of documentary, but with a great deal of re-enactment. It feels natural to people, possibly because we're steeped in it. This is after all also the essence of a great deal of commercial photography.
We've arrived at a curious juncture in which the camera, whose claim to fame is that it records reality and truth, is called upon to record instead artifice and re-enactment. While it records, naturally, a likeness, the point of the exercise is to record the artifice.
Personally, I don't much like it, I think the seams are altogether too often much too visible. I believe that the reasons the seams are too often visible is because the entire enterprise flies in the face of photography, philosophically, and that therefore to pull it off well you need a great deal of skill in areas that all too often the photographers don't even recognize as areas of expertise.
While satisfying to the customers, it looks fake, because it is fake and because the photographer doesn't have the directorial skill to extract something else.
To be fair, extracting naturalistic performances from people is widely recognized as monumentally difficult. Ask your theater nerd friends.