ET3D: I don't see why you think it works that way, when it's clear that a lot of people are risk averse, and not interested in buying an incomplete game. By this reasoning projects on Kickstarter, especially those which continue to sell the game throughout development, would expect few sales, but that's not necessarily how it works. If the games ends up well, the large number of people who don't buy incomplete games will buy it.
That's not what I'm saying. I am overwhelmingly the kind of buyer who won't buy until the game is complete, and I'm sure there are many others. But by bundling the game they are getting it very cheaply into the hands of users, including those like myself who wouldn't have picked up in advance otherwise. Now they have lost that sale to me, and to anyone else who would have waited for the final version.
ET3D: The main problem with releasing a game before it's ready is that it can leave a bad taste in gamers' mouths, which translates to bad reviews. People searching for the game after it's released will find these reviews, even if the game has been greatly improved.
Prices play very little into it, IMO. From a monetary point of view it's vastly preferable to get paid for an incomplete game than not get paid and as a result not have the game released. That and feedback at an early stage are the major benefit of early access.
The problem is that these don't happen in a vacuum. When you get a lot of poorly done early releases, and couple them with games that never get properly finished, then you build up a hostile marketplace that makes it harder in general for games to get made at a fair profit for the devs. Unless you're one of those dickhead devs who is content with "hey, I got my money, enjoy your unfinished game bitches!", no one prospers from this mechanism.
ET3D: As for prices, most indies report that sales are where they make most of their money, so the price point set doesn't necessarily matter that much. It's just a way to make sales look better, and perhaps get a few suckers.
They are still cutting into their buyer base, which is finite, by harvesting the fruit before it's ripe.
Anyway, I'm done talking about this. It's tedious now and I've made the points I want to. Ultimately the market is a complex system and there is no one pattern that applies to all of it, so one must understand the myriad nuances that go into it. You either do or you don't (impersonal you usage).