I don’t know how defensive runs saved is calculated, but if it’s a cumulative state then the more balls that are hit in play, the more of that stat is possible.
It makes sense that a team with a pitching staff that faced more batters and gave up more base runners could accumulate more.
Molina is a great throwing catcher, probably the best of his generation. I do not think he is a great receiver. He can even be a bit sloppy at times. He can hit some. To me he’s a HOFer, but he is not Bench. Not by a long shot.