Obviously it's the perfect storm, but I can't agree that it's a must to have a good hit percentage.
Bookies look at both teams, setting the total and if one team has a reason for the total to be different then their usual stats/ what bookies or public think - it should hit as well.
I remember, back when Bogut was in Milwaukee, I bet almost all of their games totals, with one simple logic. Over when he was injured (and that was a lot), Under when he played. It resulted in 70+% hit rate.
When Perkins was traded to the Thunder and was healthy (he came injured), I took Unders in all their games, till books adjusted.
Chandler in the Knicks - Under with him, Over without him - wasn't even close to Bogut's bets hit rate, but still - made some logic and profit (55% if I remember correct - in certain spots that I picked).
My point is that I believe that one team can influence the total and even more, one player, anchor on defense or offense can influence the total. Just need to find the right spots imho.