Fights that will end up on the ground, eventually:
Fights in which the grappler is the better skilled and wants it on the ground.
Fights where the bigger and stronger individual wants it on the ground.
Fights where people "fall" to the ground.
Fights where footing is in question
Fights where going to the ground is a "best option" for both fighters.
Fights where there is more grappling than striking.
And a few others.
Do 90% or more of the fights end up on the ground?
Nope.
Do more fights end up on the ground than not?
Yep.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !