So one way is to play up the importance and intangible nature of photography "oh it's so excellent and the reason you can't tell how excellent it is is because you are ignorant". This is the way a lot of other fields have approached the problem of intangibility (look at luxury brands, look at designer haircuts, look at upscale fashion designers)
Actually, I think this is a very real problem, but possibly the analogy could do with a bit of tweaking.
I am very much against the whole emperor's new clothes thing myself. I'm not quite sure how the other fields you mentioned have approached the problem of intangibility, but I suspect most of them can fall back on their brand. That's not something many photographers have the luxury of. But I don't get "contemporary" photography, in the same way that I often don't get modern art. As I've said before, Piet Mondrian and Jackson Pollock baffle me, and if that makes me one of the ignorant then great. But I feel the same way about photography.
I know Ian's raised the example of Annie Leibovitz, whose work I make no comment on the quality of. But she is one of those people who could survive on a "brand".
I like my photography to be real and tangible, and in many ways I think it can be tangible. I like photographs that make people go "wow" regardless of where they see it, not only because they've seen it in a museum or on a famous art website. That's fairly tangible, because they exist.
So going back to the tweaking of the analogy; I think to me good professional photography is a bit akin to good quality bags or such like, in terms of quality of workmanship and materials used. Most people holding it in their hands would know it was a work of quality, rather than because they've seen a small logo somewhere. (Note: I am not saying that quality and brands are mutually exclusive.)
It would be nice if photographers actually got together and figured something out, like the way the wedding photographers did
It's not going to happen. It's an unregulated industry unfortunately. And I know I've dismissed excessive connections between professional photography and art, but in this area they are linked - this isn't going to happen in the same way that you're not going to get a recognised standard of painters or sculptors.
And personally, I'm not sure how effective the wedding photographers are in Singapore, so I'm not sure they have "figured something out". But over where I am in the UK I wouldn't say they've done it particularly effectively at all. At the end of the day for something like that to succeed, Joe Public (ie someone with no interest in photography at all) is going to have to know about that organisation. You need to be massive for that to happen. So for instance, ask someone with no interest in photography to name several brands in photography, and that organisation will need to be one of those names for it to work.
I'd guess most would say Nikon, Canon, Kodak, maybe Fuji. Maybe one or two others. But we're talking major, major names. I would be amazed if more than 1 out of 10 wedding couples in this country have any clue what the Guild of Wedding Photographers or the MPA is, or any other similar organisation. In addition to knowing about them, they have to believe in what they stand for and believe in their quality. In all honesty, even Getty is a push, and they're to photographic agencies what Microsoft is to... erm... the known universe