>Why don't we just make a platform that crawls the internet for videos and build a recommendation algorithm. Therefore no matter where you host your videos you'll be easily discover?Because there are fundamental tradeoffs of _information_ and _meta_information_ that a system has that factors into recommendations.
People upload about ~500 hours of videos to Youtube every minute.[1]
Yes, that means that centralization to that degree has negatives such as the guitar channel being deleted but it also has positives such as better (not foolproof -- but relatively better) detection of spam and mistitled content. Because Youtube servers actually have the real bytes of actual videos, they can scrub the content with machine learning algorithms augmented with some human oversight.
If you only have a platform that crawls for video urls and doesn't actually ingest the petabytes of video like Youtube, the "recommendations-only" service will be susceptible to gaming such as people putting "Emma Watson and Scarlett Johansson nudes" as the titles but the actual video is an ad for somebody trying to sell a used car. Or the first few days of a video url has "Tips to deal with COVID" which is real but the video hoster later switches it out to be a video for that same url to be something else.
Also, a centralized service like Youtube can measure actual user behavior such as "watch time" (because Youtube's servers know they are sending bytes to the client) to see if the video is actually engaging viewers and this factors into future recommendations. If web surfers are closing out a 10 minute video after 20 seconds, the videos are appropriately penalized because users are "voting" that the content is bad. I.e. the viewers "voted" without even having to press the "thumbs down" button.
A new platform to recommend videos pointing to decentralized video hosting has advantages but also has unavoidable disadvantages that lower the quality of the recommendations.
EDIT to add my previous comments about the financial incentives (ads) that help video content creators which many techies overlook: https://news.ycombinator.com/item?id=21506992
[1] https://www.google.com/search?q=upload+about+~500+hours+of+v...