I wouldn't really say that is directly related to crowd-funding, though. Anything that's crowd-funded and on a retro console is obviously a homebrew (or otherwise unlicensed), and when you're talking amateur-made products, there's usually little chance that they'll compete with the best official games, since those were professional efforts created by teams of people funded by big publishers and designed with big sales in mind.

If you don't limit it to new games for retro consoles, I think there are plenty of great games that have come out of crowd-funding. But the campaigns themselves are often problematic. In most cases, I would prefer to just buy a game later on the regular way than deal with the frustrations of being a backer.