I think most of channel 7's motorsports comentators have retired or started calling the race horses. (poor buggers). I think channel 7 used to call themselves the home of sport.. that has gone by the wayside though. Still if they are going to have to cover the cost somehow so i doubt they would kill the coverage off and make a big loss on the taxi cabs. Personally I think its there is some old nostalgic types on there that used to like the coverage on what they used to have eg AFL, Grp A, ect. maybe the seasons might change for the taxi cabs say to be covered over the off season of AFL, nice summer days, least it will be something interesting over xmas specials.
To be honest though.. in TV talk i see a change of the guard of sitting down and watching tv at times on when the shows are broadcasted. Instead you download the episode (whether that is its release time of say 830pm monday night) or live or delayed coverage of a sports event. you pick the time you want to view it (its great for stats too). all 7, 9 and 10 are investing hevily in there websites and most people now are taking up broadband and a ever increasing rate. I think it will me more like picking up the tv guide as like a menu and picking something... instead of waiting for a certain time to watch things.