Yosemite got to its current condition through erosion. That’s the eventual fate of all mountain ranges. Same thing for the Rockies. The Appalachian were once a massive range as high in some estimates as the Himalayas are now.
Quite right!
In fact being from the east coast (upstate NY’er) I actually mentioned that fact about the Appalachians to my next door neighbor.
And the way the Hudson river in NY was formed by collision, a collision of a mini-continent New England into New York.