> in a relative sense the gap between "empty numb void" and "hiking at home (plus grand canyon videos)" is far far greater than the gap between "hiking at home (plus grand canyon videos)" and "actual grand canyon".

Have you ever been to a place which is really high up? You're above the trees and can not only see as far as the curvature of the earth allows you to, but are high enough that the curvature of the earth allows you to see for miles. The air is thinner so it's easier to take a breath yet harder to catch it. Your sweat evaporates faster but a breeze doesn't cool you as much. The sun is brighter, rises earlier and sets later. The wildlife makes unfamiliar sounds and sound itself is changed. Even the same food tastes different.

It's not something you can get by sitting at home and changing the background on your computer.