The way I see it, if Ridley doesn't get in this time, there's going to be backlash, and a hell of a lot of it. Depending on whether an interviewer brings it up with Sakurai again, and depending on his response, the fanbase may end up reacting any number of different ways. If there's even a remote chance left by a Sakurai response that he could work in the future, the fanbase will stay strong.
If not, yeah, the bandwagoners are probably going to drop out, but the more dedicated fans are going to invest more time and effort into demonstrating that, yes, Ridley can work, no matter what Sakurai says. This means more sketches, more models, Ridley being added into Project M, SSB4 being hacked to add a playable Ridley...Not to mention fans will feel obligated to defend themselves against the vocal TooBigots, and thus remain in continued support of the character. And should any of this reach Sakurai and/or his replacement, who knows whether a change of heart could happen. Wouldn't be the first time.
I think the "it's now or never" mentality is more of an arbitrary dramatization by a few vocal individuals, along the lines of "these characters are in a bloodthirsty death match to Rep this series in this single Slot." Eh.