increasing the blocksize (perhaps by a more conservative amount) is something that core could easily adopt, negating any advantage of BCH.
Not easily. They would need to convince 51%+ of the miners, including the miners they treated badly in the past...and unbrainwash their followers
to believe HF are no longer bad , etc... there is a big risk of a chain split.
plus there is still the absense of segwit ,and also decentralized development, which are nice advantages to BCH.
Besides, why would core change their plans to allow capacity increase? It defeats the point of everything they want.