Joe M. I don't think the simple logic works that simply mate. Channel 9 & 7's digital channels are intended to be low cost content-high margin vehicles - that is their strategic direction. The whole freeview thing is based about providing alternates to the big foxtel channels like 101, Fox8 etc which deliver very similar content but which always form part of "base" foxtel package. One HD to their credit livened up the freeview mix with their all sport digital channel, and the jury is still out on whether they can be profitable, albeit they may be marginally proiftable now.
The NBL MIGHT rate (unlikely given history) but even then it is rating at a much higher content cost than reruns of Two and 1/2 men and Hogan's heroes. As such it would hurt margins for channels like Go!, who are not about sport at all and have very clearly differentiated themselves.
That is a different scenario to One HD, who need to provide specific content for their strategy (sport) and in their particular segment "live" is King. Reruns of NBL do not cut it except as filler. One HD bought NBL not because they saw significant benefit in it specifically or massive ratings, but because it fills the 'live" commitment they need to make to be seen as a legitimate sports broadcaster - particularly in summer where they have no rights to tennis or cricket, and cannot get a crack at soccer for at least a couple of years.
TV is heading towards specialised channels. Pay TV brought it and FTA Digital is now reinforcing it. They will not put NBL on Go!, rating or not, or any other general entertainment digital channel.
You are right that if it does rate (and it would have to be spectacular), then maybe you can convince 7 or 9 to go to their traditional "mixed business" channel with it. But there are a lot of "if's" there.
If NBL makes the ratings work, then it will be on Ten at some point, not on OneHD - that would be a rewal feather in their cap.