I always wondered why YouTube themselves didn't start restricting sponsored segments. I don't necessarily agree with the idea (not a big fan of how restrictive youtube already is) but I always thought it was odd they were ok with their premium offering being devalued by sponsored segments.
I have YouTube Premium and on my phone I sometimes get a "Jump ahead" button that pops up on the bottom right corner when the video is in fullscreen. It doesn't just appear during sponsored segments but also during "less exciting" moments of a video like the introduction.
They could stop sponsored segments, but they couldn't stop creators and users from going to other platforms where they allow sponsored segments. They have far less control than e.g. Apple with the app store (where they literally can stop other app stores from ever coming into being, barring regulation that changes that).
If youtube stopped allowing sponsored segments that puts pressure on the market to produce such a thing. Even now creators are trying to come up with alternatives. Nothing has panned out, but something like stopping sponsored segments could very well tip a large number of people who want to get paid to find another way to get paid.
So what, even despite high-profile creators such as Practical Engineering constantly pushing for Nebula (the largest of them), it's still a fraction of their YouTube following.
People getting their own sponsors means Google doesn't need to increase rates to compensate creators. Who wouldn't take a deal for a 3rd party to pay part of your "employee" compensation if they were given a chance? Google still has plenty of sponsors going directly to them anyway.