"...or another solution"
- You don't have to pay with money, just provide some storage and bandwith. instead, that's ok too. Or perhaps. ertain clients may introduce ad based monetisation models like the way users are currently used to and just pay for the storage and bandwidth through that. The point is, nothing is free, but there are more ways than the ones that are currently most popular.
You can be legally liable in some countries but, if the authorities actually try to enforce that. they will have a tough time doing so. It took a lot to take down even the most blatant copyright violatiors like Openload, Streamango or Verystream that afaik were all centralized and thus relatively easy to target. What are the state thugs going to do, if there are millions of small scale hosts dispersed across the globe?