as we are talking about galleries and margins and selling prints...
Personally, and it may well not apply to anyone else, the best 'epiphany' I have had is that I will never make decent/any money from photography. I am an 'amateur' in the original sense, I have a love or passion for the subject. Once you accept that, you start to take images for personal reasons, rather than taking images that people might like to buy. I stress this works for me and maybe not for you.
I do sell images, I pay £10 a month to belong to a local arts council funded gallery, I put on a new show at least twice a year - really only to stretch me, learn new printing techniques. I very very rarely sell work through the gallery, most is from word of mouth or people who get my website address and then maybe approach me directly years later. This small turn over usually covers the raw materials of printing/film/chemicals. It goes no way towards my time, but that is for my own personal satisfaction and development.
Maybe one day I will be 'found' but its as likely as me winning the X factor, so I don't let it bother me, I just have fun with my photography - it's for me.
So I don't feel you are grumpy Zapsnaps, I've been there. I've sold prints at cost, run around getting them framed. Its not fun, now I charge for my time and printing costs, and if they want to pay they will, if not they won't, and mostly they won't, I don't take it personally.
The gallery model itself is probably not sustainable, almost all my sales have been over the web. Small shows get you out there and may get you some business years from now. These guys I mentioned are web based, and then rent gallery time for promotions. I get the impression they do this for love rather than money, they have 'proper' jobs.
In the UK I feel that photography is not viewed as an art, or worth as much. I enlarged an image to 30 inches x 30 inches, got it framed and delivered and hung it in this ladies house myself. She was very grateful as it had saved her 'the bother of taking the picture myself'. Photography is that easy isn't it, just point and shoot.