You cannot change keyboard shortcuts in After Effects but you can in Premier Pro. You can't change keyboard shortcuts in Bridge but you can in Photoshop. And as you've pointed out you cannot change keyboard shortcuts in Lightroom or Lightroom classic, but you can in Illustrator and InDesign.
If it makes you feel any better, people have been asking for this for ages, you are not alone.
My guess, and it is only a guess, is that the original programing structure does now allow that to happen. And why that did not happen in applications that are "relatively" new such as the Lightroom applications makes as much sense as does the fact that Crop in PS is "C" and it's "R" in Lightroom.
Lastly, the people who may know don't visit these forums and those that do are in the dark as much as yourself.