I have often thought that it must have been tough to be on the Flow team. It was pretty good, and absolutely would have been "good enough" to catch on if it weren't for TypeScript. But ultimately the better language won.
The only other context I'll add is for people shipping Flow that I knew at the time they felt that this announcement felt like it came about two years too late. I had already switched to TypeScript long before because, in part, of the things they're apologizing for in that article which were evident long before being said out loud. I say that with great reverence and respect for the people that worked so hard on Flow, by the way, but that's the situation I experienced.