The problem is not really a technical issue. It might be expensive, but it's not rocket science to create a Youtube competitor.
The problem is that in order to build a 'viable' Youtube competitor, you need to get content creators to post on your site, instead of Youtube. To do that, you need to be able to guarantee them ad income, and to do that you need advertisers, and to get them you need a large number of viewers, to get whom you need content creators posting on your site.
Whoever manages to find a way to solve this chicken and egg problem will end up creating the first viable Youtube competitor.
> The biggest problem is being able to handle the legal minefield that Copyright law (in all its international variations) is for a video plattform.
That's not that big a problem tbh. It's understood and there's a lot of solutions.
The bigger issue is that you'll have to get music licenses if you want to actually run a service in the long run, and people's faces tend to drop when they find out they simply can't license music internationally, and you have to approach multiple different bodies in literally every individual country you operate in.
Operating an international video service probably requires you to sign 750-ish collective rights agreements, and that is painfully expensive to even negotiate. Some of these bodies are also much more rational than others on pricing.
The problem is that in order to build a 'viable' Youtube competitor, you need to get content creators to post on your site, instead of Youtube. To do that, you need to be able to guarantee them ad income, and to do that you need advertisers, and to get them you need a large number of viewers, to get whom you need content creators posting on your site.
Whoever manages to find a way to solve this chicken and egg problem will end up creating the first viable Youtube competitor.