bec most of their teams historically have been built to take advantage of the wall. Unfortunately that's a 2 edged sword since half the games take place outside the park so the "advantage" isn't much of one anywhere else.
I'd love to see some stats on how many home runs typically go over the monster at Fenway that would be outs elsewhere and how many balls that bounce off the wall would be homers elsewhere. I don't think it's the advantage that your insinuating.