I think that's the most likely outcome. Google already pushes the current WebKit version of Chrome for iOS hard and that will only intensify once a Blink-based

I think that's the most likely outcome. Google already pushes the current WebKit version of Chrome for iOS hard and that will only intensify once a Blink-based version is possible. Even if Mozilla goes on an all-out marketing blitz to try to boost usership a Gecko-based Firefox for iOS, I don't think they stand a chance. The number of eyeballs seeing Chrome promotions is simply too much greater than those seeing Firefox promotions. It would be nice if Gecko were the only alternative engine available on iOS, because that'd be a huge boost for overall web engine diversity but it's hard to envision a scenario in which that happens.