Update: Nov. 11
Julia Alexander has explained this "viability" language in an article today in "The Verge", "You Tube says it has 'no obligation' to host anyone's video", and explains that the "commercial" language had been there in 2018 without being noticed. The change is that it may remove content at its "sole discretion" if it doesn't want to host it. But the literal language in the document seems to tie such an event to a "service change". The article acknowledges that some creators were concerned that they could be removed if they didn't generate revenue (that has to do with the "pays for itself" idea I have been discussing recently myself, since early 2018 -- reminder video). But this interpretation is not correct, at least according to most legal sources or to Vox.