I've thought about this as well, but bandwidth still seems too expensive to be viable.

I pay $10usd/TB. Assume (worst case) 1GB/hour because its a beach scene with waves or something and you've already got about 3/4 TB/month/user. You'd have to charge more than $7usd/user/month just to break even. That feels a little steep.

Even low speeds add up to big transfer if they're "always on".

I always thought cable TV providers ought to do this with their gazzllion extra channels that they never seem to be able to find enough programming for but the most impressive use along these lines I've seen them do yet is "24 hours of yule" at Christmas time where they broadcast a loop of a burning log for a day straight.