Yes, a lot of it is a scam, and auction houses definitely do that shill bidding thing, but I don't think it's true of most commercial galleries that you can trust. They don't sell the work at different prices to different collectors. That's a bunch of bull and that would put them out of business. That is done among certain shady galleries and we're talking about the high-end galleries that carry art "stars." Those are the places that make arbitrary pricing on work. Usually, prices can be mostly justified by past sales and the artist's resume, what collections they are already in, etc. It doesn't have to do with auction houses, that's a whole other game.
There are other scams--galleries that will sell for way more than they tell their artists, or not pay them at all. They are infamous for it, yet artists continue to work with them because of their "prestige." ACE Gallery in Los Angeles is one such gallery. It's no secret, but he reps many notable artists anyway. How does he get away with it? No idea. I've almost worked with another guy in Atlanta who once had a gallery in Santa Monica. He did the same thing. Luckily, I was warned by some good friends and I looked into him. I came to find that was no secret either, yet I knew people who worked with him anyway because they still got thousands of dollars off sales. That's a fraction of what he got though. That sort of thing happens more often than these other scams. It happens a ton.
Anyway, this thing about "striking it rich" and then claiming it's all "based on pure merit" is not exactly fair to say, nor is it really true in most cases. It's just something to say, repeat, generalize, and justify for yourself when you don't know the details of other people's successes. It's not based on any factual statistics. Yes, luck plays a part in everyone's life in every type of business, and in every circumstance, including what family you are born into. And misfortune plays a huge role as well. What about overcoming bad circumstances and hard work? And how can one control what collectors like and want to buy? How can you fault artists for any of that?
"Striking it rich" is also a lot of crap. Galleries make more than the artists. The collectors are way more wealthier than the artists, and most decent occupations are not only reliable, but they provide a better living across the board, usually with benefits. Very, very few artists become rich art stars. You're talking about a tiny percentage. You're talking about the ones (that are alive) that make millions. Jeff Koons and Hirst. Otherwise, it's more like thousands of dollars (not enough to live a wealthy life) and it's fleeting.
I agree there is a lot of whacky, scammy, dirty dealings in the art market, but I don't believe it is the norm among reputable businesses that have been around for decades and sell regularly to their clientele. I'm not talking about the super high-end, but I'm talking about galleries that sell art up into the tens, twenties, maybe thirties of thousands, or thereabouts.