I'm reminded of the origin of Youtube - loads of video startups tried a similar thing, until the underlying tech became sufficient, and Youtube found the sweet spot of product-market fit (with enough capital to run at a loss for long enough).

These kind of video portals may not be quite viable yet, but it seems like they are right around the corner. I entirely share your sentiments about cable TV.

Something like this (like Youtube in it's time) seems inevitable - it's exciting to imagine the effect this sort of thing will have on the world.