YouTube pushes whatever format feels popular to them at the time, like when they started giving absurd weight to shorts.

Even content creators that pretty much only do long, focussed videos started to hack useless bits of them to put in shorts as an aside, just because the algorithm would make their channel basically invisible without a few of them.

If youtube starts the same kind of shit with vertical streaming, you can be sure they’re going to pop everywhere, no matter how fitting the format is.