Most would go to other airlines
That might be entirely possible, however, I expect a good many would stay (especially those nearing retirement), and just think of the stacks of applications that are in the HR files, and the potential pilots just waiting for possible openings.
CX is, by most any measure, still a quite good job, and I expect few would be willing to cash in their chips over some hothead's industrial action ideas.
IE: talk is cheap, actual action a bit more difficult.