Personally I think you're way overgeneralizing.
The knock on Red Sox teams of the 70's in particular was that they relied too much on the long ball, remember?
The 1978 team had 74 stolen bases.
The 2018 team has 45 already.
But I'm not denying that we've seen a huge trend toward going for the long ball the last couple of years, which there are numerous theories for such as the prevalence of shifts.