For a video serving platform in a vacuum, maybe it would be the best financing model. But Youtube doesn't exist in a vacuum. And supporting them as it stands means rewarding them for their malicious practices, even if you yourself can work around them. Youtube isn't going to magically become decent and friendly by getting more money. Rewarding them anyways is how you get companies that feel empowered to put their own profits before the common good and the good of the customers. It is enabling yourself and others to be squeezed hard should enough people pay for premium and they suddenly close down yt-dlp and free tier viewing in general. Youtube is a near monopoly already, and treating it as if it's just some small company trying it's best is extremely dangerous and objectionable. Again, not saying having premium is necessarily bad, but it very clearly is not a safe or recommendable deal that most people should take unless Youtube changes their tune drastically to show they can be trusted with more power than they already have.

You're missing my point on the distribution of the donations. If 5 people watch the same 5 creators 20% of the time, then the outcome is the same if everyone pays a dollar to every creator, or if each person pays 5 dollar to one of the 5 creators. Online platforms operate at scale, not at the individual level, so having superfans that donate to you directly and are more likely to keep supporting you over longer periods is much better and financially secure than getting a few pennies from someone. It's as you said, sometimes people provide way more value to you than your watch history would reveal, in which case a direct donation is superior to make sure they get what they deserve.