This question is important because my belief has always been that if something else wins out, core will adjust and may again become the best client, however, what the best developers do is far more important than what core does. So as a developer with "nearly a lifetime of relevant experience" that helps to "identify initiatives which are likely to be successful" I'm interested in whether he would jump ship if he had to (supporting classic or unlimited, for instance) and also in whether or not he would believe he had to (vs expecting the ~75%/+ longer fork to die off without confidence in the ~25%/- fork concurrently being so shaken that there is no longer a "successful initiative" on either "side").
Many of the people pushing for hardfork size increases are pushing a vision of Bitcoin that will almost certainly become highly centralized-- See for example the comments on Reddit today with people arguing that it's possible to handle 8GB blocks using computing systems at quasi-youtube scale-- some don't consider this a problem; from my perspective such a system would be completely uninteresting (and a detriment to mankind, if it survived at all).
No one _has_ to support anything here they don't want to; and I'm surely not going to support something that puts us on that route and I doubt practically any of the active development community would. Presumably anyone okay with that path would already be supporting Bitcoin "Classic", but clearly
none are.