I'll play devils advocate here, and say that I could potentially see this idea working. The difference between this and the plethora of different video services, is that the product here may not be the actual video service, but can be seen as a way to support the various video creators. Most of the creators on Nebula are already drawing in pretty large followings on Patreon, so it's clear that they are able to retain…
Perhaps what is actually necessary is a RSS equivalent, since I fully understand how YouTube is screwing creators. But this (and the equivalent projects, like LinusTechTips' floatplane) just seem like they are destined to follow vimeo.