Haven’t seen this one a thousand times before.

What if there were still ponies around, but they all live somewhere else?

Sounds interesting.
 
Faved.

Or what if it was the end result of all futures shown?

i personally think that it was starlight’s timeline and she tried confiscating Holder’s Boulder from the rock farm to seize in the name of Equestria, and this is the aftermath of that
 
as good an explanation as any