In October 2015, right between the two Scaling Bitcoin conferences, Bitcoin Core contributors Eric Lombrozo, Pieter Wuille, Wladimir van der Laan and Luke Dashjr discussed a potential new model for soft forks on IRC. During this chat, Dashjr pointed out that the proposed mechanism wouldn’t work for all potential soft forks, like a SegWit soft fork.
Interestingly, what Dashjr considered obvious — the option to deploy SegWit as a soft fork — had not even been considered by others at all. And even Dashjr didn’t seem to realize the implications of this possibility at first.