Honestly my biggest worry right now is that Bare Mettle is going to be forced into another Kickstarter, which is normally PR suicide and doesn't look good for them at all. Hopefully we can at least see a finished game before things get so dire, but with so many KS failures as of late, I won't hold my breath.
I don't think what happened to other Kickstarter projects determines the likelihood of Sui Generis succeeding or failing. Kickstarter is just a way to earn funding. What the people choose to do with the funding is completely up to them. Obviously some people are better at managing funds than others.
I think very few game developers are as dedicated to their game as the Bare Mettle team is. They've quit their jobs and relocated so that they could devote their entire lives to making Sui Generis. It wasn't just something they thought of doing on a whim. I think they'll do whatever it takes to make Sui Generis a reality.
The team knew that Sui Generis wasn't going to be easy to make since many of the techniques and mechanics they are using have never been done before so they'd have to create and engineer everything from scratch. This requires a lot of trial and error and testing to determine what does and does not work until they find a solution that is viable and meets their requirements.
So far they have shown that they are more than capable of achieving their goals by releasing the alpha and beta versions which deliver what they promised: physics-driven combat with a slotless inventory system. Yes, it may require more time than originally estimated but most games do. This is nothing new for game development and completely normal. Considering the complexity of what Bare Mettle is attempting to pioneer in Sui Generis this is especially true.
However, I highly doubt they'd do a second Kickstarter campaign. I believe they'll secure more funds by releasing an early version of the game and keep adding in features post release.