Do you have an estimate on how long the gradual process took to complete for the case you bring up?
I think there is a truism that just can't be gotten around. The different approaches to distribution release timescale being used by Debian versus Fedora greatly influence decision making.
I think there is a lot of truth to the idea that Debian's "release when its ready" approach with much longer timescales between official releases of a stable offering is more aligned with gradual technology transitions.
I also think that the Fedora twice yearly release cycle timescale imposes constraints which weigh against gradual processes in favor of distinct coordinated transitions.
And I further believe that this is an entirely okay situation as Debian and Fedora as projects put the emphasis on very different priorities in their project focus. Hopefully the good new ideas will cross-pollinate. And the bad ideas will be allowed to quietly be allowed to taken outback and shot.