Hard to believe tennis is more popular than cricket. Channel 10 made the Big Bash one of the hottest properties in town, with the proper backing, I would think it would far outstrip the tennis. CA made a huge mistake not going with Channel 10 just to try and scrape over the $1 billion mark. They were going to anchor the whole summer around it.
For summer sports success isn't gauged on the number of eyeballs that watch the sport but of the number of eyeballs that continue with the network afterwards. Tennis has proved to be a better lead-in than cricket. MKR is a good example. Was a ratings juggernaut when it followed the tennis but immediately collapsed when Seven switched to cricket. Even during the BBL's golden era Ten was never able to convert the audience to regular viewers.