Partly it was because back in 2011 no-one imagined that a phone could run full minecraft so they conceived of it as a simpler, cut down version. Then hardware improved etc.
Almost any serious mod packs won't fit on games consoles or cheap tablets. MC Eternal even struggles in 16GB of RAM.
Do you get something for that? Sure. The first six months I played MC Eternal I was still finding random drops from mods I'd never seen before, I fought monsters yesterday I didn't know existed last week. And beyond suspecting that the moon is actually literally made of cheese (thus explaining where the rat civilisation went) I haven't even started on space travel yet.
On a PC you can run a large pack slowly on a medium sized PC, or reach inside and (for solo play) rip out the biggest pieces you care least about. Neither of those sound practical for a Switch.
I'm sure a PS5 could run most packs if somehow they were functional, but I'm also sure most Minecraft players don't have a PS5.
