YouTube links to Twitter and Facebook and all those other sites because Facebook and Twitter aren't video-streaming platforms. There is nothing to compete over. They're not the same type of business, so they have completely different corners of the market. You could make the argument that Twitter and Facebook "colluding" is suspicious but even then, people (mainly in Gen Z) are already leaving Facebook and Twitter in droves, not because of any political stuff but because they've realized that talking to people online and posting political memes to "own the X" is soul-suckingly depressing and they prefer to interact with people in real life and to get stuff done instead of sitting on their asses and complaining all day.
The reason all these start-up websites keep failing isn't because of "duh ebil monopolees", it's because there's no pull for people that aren't political. Nothing about any of these platforms (Minds, Gab, BitChute, etc.) is any different from the big competitors except for a "commitment to free speech", which materializes itself as a bunch of no-name political personalities and Humble Water Filter Merchant flooding the platform and making it basically impractical to post anything there that isn't "LIBERAL SJW GETS KARMA PWNED #OWNTHELIBS #Annoying Orange2020". There's a reason people say to make something out of passion rather than out of spite. Do you think someone like JaidenAnimations or Markiplier is going to start posting their videos to BitChute in the near future? No, they're not, because BitChute is occupied solely by Humble Water Filter Merchant and random right-wing yahoos at the moment. The only people who go on BitChute are there to see political content. Not only would they be called national socialists for even considering making the move, but once they made the move no one would even watch them and they'd go right back to YouTube in a heartbeat.
If BitChute actually wants to survive and flourish, they'll ban overtly political content for a year or two and try to make the platform more apolitical by bringing in content creators disenfranchised by YouTube's algorithm. Imagine the old animators (Egoraptor, Oney, Ricepirate, etc.) all posting new content on the platform. If you get good creators to come onto the site and post videos and promote it, people will come. BitChute is already made to promote good content-making. I talked about how the Patreon-style payment system means that creators wouldn't have to rely on making advertiser-friendly content, which means they could get more personal with their content and wouldn't have to post it as often. Imagine Emplemon's rant about how old YouTube was the best, except fully realized into a sustainable business model. If played right, that's what you'd be able to get out of BitChute, and that could absolutely compete with YouTube without a doubt. Then when BitChute is well established, they could push the free speech angle. Until then, it's just going to drag the site down.