Obviouly he is right, a lot of games do not even support split screen coop... it's kind of self ful filling really!
Anyway, I never play online coop, not that I have not tried it, I just find it un-interesting...
However, when I have friends over, depending who, we like to sit and pass the controller around while we talk... or play together if we have a multi-player game, last time we played Streets of Rage 2!!! there is no modern replacement 
The real reasoning is that people who play online coop pay for xbox live gold, they essentially "buy" the feature, while the local coop players are a bunch of free loaders (or as Phil says, this is where the market is going).







