That said: making a YouTube is a hell of a lot of work and a huge investment. Yes I'm sure you can kludge up a simple clone of the basics in Your Favorite Language in six hours, but can you build the infrastructure to deal with the inevitable copyright infringement, avoid falling foul to widely varying obscenity laws across the globe, hire people to screen for that sort of thing, there's a whole bunch of stuff above and beyond "managing some AWS virtual storage for video files".
As I know, current Patreon's stance on what to do with it when they reach that stage, is to focus on English speaking speaking audience, and have no legal presence outside of US.
As the US is the only paying off market for 9 out of 10 of any online media businesses, it makes sense.
Same thing with CDN, if they go that way, they only have to deal with much smaller loads, and have no need for multi-dc replication.
If they only have to deal with the most creative and valuable share of makers that they will skim from yt, the will not have to deal with exabytes of cat videos and other garbage content.
Same on the legal from, for as long as most content is original, the only issue will most likely be music, but there is already a thriving industry of RIAA-free music licensing specifically for makers thanks to YT yielding to requests for automated takedowns/DeMo/and revenue divertions.
Maker relationships? Very straight, steal top 10% makers from YT, depriving it of majority of genuine creative content. Here YT can't counter that with pretty much anything: Google sells ads, Patreon sells makers themselves. Google stays with cat videos, while Patreoners take the tasty stuff.
Predicament looks rather dim for YT unless they will have the willpower to make a U-turn in their relationship with the creative community
And that's apt to get worse with paid prioritization; large incumbent players can already use these kinds of money sinks as loss leaders for other products, but adding reduced negotiating leverage to the massive capital barriers is just the nail in any prospective startup's coffin.