It costs an enormous amount of money to host video content, doubly so when you need to replicate it across servers. I have never seen another company come close to usurping them.
Yeah, The problem is, the price on YouTube is so incredibly expensive because we have to pay for a million script kiddies worth of useless videos to be uploaded and permanently stored everyday.
If someone made a competing system where you had to pay a small amount to host a video and then it turned around and paid you once you've got enough eyeballs that would be a far more sustainable model and cause people to police their old underperforming content.
I think its more likely that YouTube will shut down and be replaced by nothing. Its existence has never made sense as anything but an act of charity from an organization with tech resources to burn.
There are a lot of unprofitable startups that get purchased speculatively based on other factors like their user count. The idea being the buyer thinks they can monetize.