There is merit to replacing batteries proactively. Commonly, a battery is considered worn if it can't hold reserves to 80% of new. We all probably use them beyond that. Problem is as the battery gets further worn, load handling also gets impacted sagging with lower and lower voltages. That's a potential issue for the electrical system as for many inductive loads like a motor for example, if it can't get proper voltage, it will draw more corresponding current to make the power it needs to do something.
Many electrical elements are often primarily rated for current as that's what builds heat. So things like the starter relay, transfer case actuator, fuel pump and controller, tailgate lift actuator... It's wholly possible that these failure points at higher mileage are exacerbated by worn batteries.
Talking to a buddy who was a previous Ford electronics integration engineer, they test for similar issues to make sure electronics have sufficient margin to handle off-nominal conditions. He shared a story where reliability issues could stem from saving 10 cents on a part that didn't have enough margin.