This seems like it would be the worst time to launch a competitor. You'd be saying "check out this new site, it's like YouTube but we brought back the ads".
If this new contract is actually an issue, it'll still take a little while for people to understand the downsides, and that's when you want to launch your "creator-friendly YouTube" or whatever.
You could wait for the problems to get worse to launch it, or you could offer a working platform now [if you had it] and switch to a totally-free model. As long as you have capital, burn through it to pay for everything until you have enough users. Then, after a year or two, introduce ads, or a subscription fee, or sell product placement or something.
I still don't get why product placement isn't used in place of ads. It could bring in tons of money, possibly more than ads, for the most popular youtube channels.
There's lots of product placement, but YouTube doesn't get any of that money. Companies go straight to the channels when they want to advertise. I don't think YouTube could get away with a contract that gave themselves a cut of this money.
How does exclusivity there work? Probably most content on YouTube is only uploaded there by the creators but that doesn't stop Facebook being covered in stuff stolen from there - if vessel got popular wouldn't the same happen?
If this new contract is actually an issue, it'll still take a little while for people to understand the downsides, and that's when you want to launch your "creator-friendly YouTube" or whatever.