"Crowdfunding is supposed to help with getting the initial capital. What
happens when you need more money to deliver your project and sustain it for
years? Are you going to alienate and piss off your original investors if you
cannot meet those demands?"
If it turns out that the initial crowdfund goal was not sufficient to deliver
the project, that reflects poor planning on the project leadership (oops, we
underestimated the full cost of this) and not a fundamental flaw in the
crowdfunding project.
Crowdfunding's only one idea but could also be used for a second round of
funding too. Also there's subscriptions. This is especially good if it's a
project that needs ongoing support. I think the subscription model was used
for Ryzom. As I've said, you're limited only by your imagination. The
pre-order system's also been used and as I pointed out earlier has some
similarities to crowfunding such that there may not be a reason to draw much
difference between the two.