As if any sizable competitor wouldn't also be faced with the compromise proposed by media conglomerates: "allow us to monetize stuff we claim without utilizing the DMCA or lose access to hosting our content (music videos, movies, clips, etc)".
The only one that might work is if they charged a reasonable fee and only allowed people that had uploaded government issued IDs and accepted liability for their accounts. That might help sufficiently deter bad actors and reduce labor costs to sift through all the garbage.
That is completely ignoring the network effects of everyone being on YouTube. The profitability of an alternate website while YouTube still exists has nothing to do with the profitability of a YouTube without music.