I think dubious is overstating it, but being cautious is smart. The projects I have backed are all by well known devs with a solid reputation and some high quality releases behind them. Thats not to say that means their games will be good, or even released but for me at least it does make them a more viable option and far more likely to meet my expectations. I've been having a pretty good conversation with Darren from Obsidian for the last month about P.E and I am confident the game will be exceptional, but the fear of commercial failure is still there. He admits there is a lot of risk here. Failure to produce the game the backers want could cause significant damage to the brand that a publisher backed title never would. A failure here could be seen as a personal failure to the people who now feel they have a stake not only in the game, but the company making it. The fallout could be far reaching and irreversible should it fail to meet expectations.
The thing some people dont grasp though is that crowd sourced dev teams are not sustainable long term. They cant exist, or more accurately subsist on that model. As they will be operating project to project with no safety net should something go wrong. Unlike publisher backed projects there is no avenue for extra funds, and a delay could cause the game to fail and that would essentially destroy the company.
The game needs to be successful enough outside of the initial backers to make enough money to act as a buffer/safety net for their next project, or even better be enough to fund at least a majority of it. Then they could crowd source for extra funds, or seek publisher money but still have enough freedom to keep to their "vision".
The small indies and passion projects will continue regardless, but for the likes of inXile, Double Fine and Obsidian, or Cloud Imperium they will require fairly significant commercial success if they want to continue to produce games of the scope they are known/aiming for. Personally I think they will, but gamers are fickle and making a great game does not equate to game sales (Planescape, Grim Fandango, Psychonauts, Vampire - Bloodlines, etc).
Still though for me at least I think crowd sourcing is the single best thing to happen to game development in a long time. The potential to open up the market here is huge. It could bring back real diversity and reinvigorate niche genres and even expand genres in to new areas not yet explored. When creators are allowed to create without needing to cow to corporate expectations a whole world of possibilities opens up. We could see the diversity of indy gaming entering the mainstream and that imo is good for everyone.