But honestly it seems like "early access" is what is filling that void.
I'd agree with that. To get on there you have to at least have
something that people can play around with right away, even if it's a little rough. Kickstarter has projects from all along the spectrum, and games have come been released coming from every stage.
If you're wary, just don't back games without demos or clear development plans. Simple as that. If it's something that you're still interested in, just wait until the game actually comes out, because there's probably enough people out there who don't care and will fund it anyway. Either that or it's so far away from its goal that your $20 won't make any difference.