The thing is that most of these sport occassions you mentioned are included in the broadcasting "crown jewels" meaning they have to be shown on terrestrial tv.
Sky and BT sport have hours of programming to fill in the summer they might just pay more for a reasonably high profile league to show. Also given they don't have much on they might help market the shit out of it. Given how awful the current marketing is that cannae be a bad thing.
Personally speaking i'm all for a shift to summer fitba, hate the idea of parting with cash to freeze my baws off watching players basically trying to stave of hypothermia