Storage is probably the easier aspect to address. Storage is cheap and decentralized storage systems have existed for decades.

The problem is bandwidth and latency. Most residential ISPs do not offer high bandwidth and low latency upstream connections, which means there's no good way to serve the content you're storing.

Residential fiber is becoming more common in some areas, but often those residential plans still limit upstream or specifically have terms in their acceptable use policy that forbid such activities. Here's an example from my fiber provider, which couldn't be clearer:

You may not use the Services to host any type of server.

It's a little silly of course, because if you were playing a game and hosting, you're probably hosting a server! But if I were serving videos to thousands of peers, I'm sure they would notice and take issue.