I guess I'm speaking from my view.
His Mission Impossible movies are getting long in the tooth.
Kind of like the Bond movies keeping their Bond when he was in his 60s.
I preferred Sean but he got too old to be that super spy with all the super moves.
Only Walker, Texas Ranger can pull that off.
Even Steven Seagal got old and in his last few movies his bloated size is what made him, not his moves.
Age creeps up on us all.