It does seem like every team used that extra roster spot for a pitcher. Teams used to carry 11 or 12 pitchers, and when they added the slot, one expected 12 or 13 pitchers, but it's almost always 13.
It seems like many posters want 9 everyday FT players who are good enough to not need to be PH for or replaced on defense later in games. If that were true, we wouldn't need a 5 man bench, but it's rarely true.
The Sox has true tremendous batters vs LHPs, who had massive splits. We also had more than 2 guys who his lefties very poorly. It made a lot of sense to platoon, and we used 2 slots for platoon- Abreu w Ref and 1B/2B w Romy. Some argued Duran should be platooned, too, but we didn't have 2 Refs, and Cora seemed to be against the idea of Duran platooning.
Now that Ref may be gone, Abrue improved vs LHPs and Romy did okay vs RHPs. maybe we will move away from that model. A lot depends on who we add. Alonso at 1B will not be platooned with Romy. Romy could platoon with Mayer or Masa, so that might not go away. I doubt we add Campbell or Garcia to the 26 as a strict, short-side platoon, so maybe that platoon ends in '26.
I'm not sure we need DHam and Sogard or Ref and Eaton. 3 catchers doesn't make sense, unless one can play elsewhere well enough.
It doesn't seem like 13 pitchers helps limit overwork and injuries, though.