There's nothing stopping creators from doing sponsored videos and/or sharing their liberapay/opencollective/patreon on peertube, they even provide a dedicated place for it.
Most of the youtubers I follow claim YouTube's direct compensation makes up very little of their overall income, especially since YouTube keeps lowering the compensation/demonetizing everything. Most of their income comes from sponsored videos, patreons, and merch sales. Maybe it depends on the youtuber but it seems consistent with those I follow.
There's also a motherearthnews article showing a simple DIY setup complete with infloor heating!