When game developers can see that people are willing to pay for beta access to games, what is their incentive to ship a polished game? Most consoles have online connectivity as well, so patching up later is usually not a problem either. I don't see this changing anytime soon, with quarterly budgets being more important than quality.
As for Fallout: New Vegas; the bugs were totally expected from anyone that played Fallout 3, which was also full of bugs. And it is not just gameplay bugs, the entire engine is extremely buggy and the game was neigh unplayable for a lot of PC players, but thankfully a very clever developer at http://www.transgaming.com/business/swiftshader made a custom D3D9.dll which corrects some of the engine bugs (like NOP all debug calls, ignore some buggy shaders, etc.):
http://www.newvegasnexus.com/downloads/file.php?id=34778 for the nVidia version.
http://www.newvegasnexus.com/downloads/file.php?id=34970 for the ATI version.
(The custom dll was made for Fallout 3 and not Fallout: New Vegas. Yet it fixes the same issues in both games.)
Note: the game is very, very good -- without the bugs. Too bad that it is the community that has to fix the bugs.