Do you think we'll ever be able to pay HBO directly for an HBO Go subscription? It's the only reason I still pay for cable -- would jump on this Roku immediately if it let me cut the cord.
In addition, most of these companies likely loathe "the internet" due to the pervasiveness of piracy. They see making their content available online directly as enabling the "thieves."
The only thing that will drive them towards acknowledgement of the need for online, direct distribution will be competition, likely from Netflix.
(Take all of this with a grain of salt. I am not any sort of cable executive, and the fact that they so frequently behave in such an illogical manner means that I'm likely wrong.)
HBO likely can become Netflix faster than Netflix can become HBO.
I'm not saying HBO won't succeed in the online space, but at least in Norway their arrogance has really hurt the perception that people have about them.