Ha, that ain't happening. Chris' brain is a
write-only memory that can only take ideas and frankenstien them into his world, you can't remove them. Especially not something as big as Ponies. He'd probably sooner have Barb die than give up his fucking ponies.
Nah, they're not going away. Much like a Discworld god, Chris' fantasies feed off the attention they get from other people. Ponies are still big (somehow), there's still Bronycons (somehow). Sonic's dead and buried, so you don't see much of that in Sonichu anymore. But ponies will be around for at least another decade, at most, so Chris is going to stay on this shit for a good, long while. Possibly for the rest of his life, sans any further unforeseen but entirely predictable psyche breaks.