With watching your response to my response it made me want to comment on some of the points you made:
YouTube is free, YouTube Red isn't compulsory and clicking "skip ad" or even just watching it doesn't cost a person financially unless they should be working rather than watching videos lol
Also, that part only affects the viewer, not the creator and can also be overcome by running an adblocker. As a creator, YouTube doesn't cost anything, they host your videos for free and even promote them too without sending you an invoice, so it is a free service.
You also mentioned that YouTube has it free, this isn't really true, purchasing and running servers, renting/buying properties to locate the servers, although I can't find details on how many people they employ, it has been suggested that around 800 and they have also stated they are planning on employing thousands of people to carry out the vetting of videos, all these people need to be paid. Currently YouTube is not running a profit, and is "still in investment mode" according to YouTube's CEO.
Regarding other platforms, Vimeo is free, but it also doesn't have the traffic and does not promote your content so it would be a very hard place to grow your channel. Amazon isn't really viable for myself as it is only available to the USA and UK, the majority of my views are from Asia and India currently so growth of my channel would still be hard and if only 3 tags are allowed then it will be even harder to find new creators as it will be swamped with other creators using the same combination of tags.
As for YouTube making money off our demonetized videos, I don't think they can as our videos are classed as not advertiser friendly and with there not being enough adverts to go around all our channels it doesn't make sense for YouTube to waste them on relatively low view count channels. If you look on any channels channel page, it shows a list of related channels, these are channels YouTube thinks your viewers may like, although what help it is to those channels I don't know as it is only viewable on that page rather than when you are in a video and once all our channels no longer generate ad revenue that list will possibly change to channels which do get them an income!
