Well, it does. But only the folks on base when they hit one.
Alonso has 44 RBI, but 15 of them were himself who was not “on base” to be driven in. He’s driven in himself more than any of his individual teammates, although he has driven in Taylor Ward 14 times. Ward, as mentioned earlier, is having a freakishly good OBP this year. Contreras has driven in himself 13 times, but hasn’t driven in any teammate more than 8 times. Sluggers with 20 HR or more often drive in themselves more than any individual teammates.
The fairest comp I use is % of baserunners driven in, which clearly favors Contreras here, 17.6% to 13.6%. For some reference, most RBI leaders drive in roughly 16-18% of all runners on base. And folks say OBP isn’t important….