There's a whole slew of shows which would whither and die without a cable subscription model.
Think Food Network or Discovery or any show which isn't a serialized story model. Would you actually buy a season of Mythbusters?* I watch those shows all the time, but usually when I'm just browsing. I'm not sure I'd actually buy them ala carte.
BTW NFL and NCAA aren't holding out on streaming. The rights to internet broadcast games are tied to their traditional cable and broadcast deals with cable providers and the Comcasts and TWCs of the world are locking in those restrictions. MLB is the only one who kept their streaming rights.
* Note I'm not saying no one would - but I don't think enough people would
I understand you, I only get cable TV for NBA finals. Then I cancel it again :) On a big TV, ESPN3 is not always great enough quality.
That said, until the NCAA and NFL are willing to provide a stand-alone service that lets me subscribe to Georgia Tech and Atlanta Falcons football games, the whole concept of ditching cable is a non-starter for me. Since I'm no longer local to Atlanta, I have to have an option for viewing. ESPN3 is great for NCAA games but requires a partner cable subscription. I still usually resort to finding illegal streams of falcons games online since I have literally no other option.
I recognize that HN might not be a bastion of football fans; but having grown up in Atlanta, GA, football is a part of fall that I'm just not willing to go without.
Live sports are really the last stronghold that cable & satellite have.