I'm a cynic and I think this is being done mostly for the added bonus of making piracy more difficult. It's the same reason I think games are 50 gb now and nobody sees that as a terrible and wasteful problem. Bigger files are harder to share.
I've been watching this forever, but I don't do kickstarter or early access as a matter of principal (I did cave for that new Carmageddon game though). I bought it and am downloading it now. I'm hoping it will scratch that itch I've had since Fallout 3 was cancelled, the real Fallout 3 I mean.