This is almost all false. Leon just turned 30, Vazquez turns 29 this summer. There is a minimal age difference. Vazquez isn't a kid anymore, and isn't getting better, and he was for some reason signed to an extension through 2022. They both suck at hitting, but Vazquez was actually worse than Leon last season. Leon is a much better defender and isn't really close. Leon last season had a 1.1 Defensive WAR. for his whole career Vazquez is a 1 WAR player, was awful last season, and isn't off a great start this year, offensively or defensively.
Vazquez sucks, and everyone knows it, except some fans in the Boston.
Also, my argument has nothing to do with Sale, just to be clear, I just think Vazquez sucks.