We have moved towards a world of centralised services because decentralised ones are—by definition—difficult to monetise for the platform/software-maintainer(s). What people want is irrelevant when all potential options have to be initially well-funded: the choice is too restrictively limited to perform an honest comparison.
> To many people it's the centralized services that "are" the Internet
That's because they dominate, because they're profitable for the central host.
> If you want to solve the problems with YouTube you have to do it with another YouTube. Build another centralized service that fixes the problems that YouTube has
The problems with YoutTube are caused by it being centralised, so this proposal is paradoxical.
> they all go from Active to Dead or Stalled
It's a difficult challenge. It's David v Goliath. Many fail.
> YouTube's audience doesn't care about anything at decentralized network has to offer. It's just entertainment for them. They just want to watch videos and shitpost in the comments.
YouTube's audience want to be able to find entertaining/useful/educational/whatever content according to what they've come to Youtube looking for, and promptly leave after having been entertained/educated/generally fulfilled. Youtube is not incentivised to give them this; in fact it's strongly incentivised to make what they're looking for as difficult to find as possible so that they'll spend hours and hours binging vacuous addictive content looking for something but never quite finding it and getting no satisfaction from the experience.
This is not something that's unique to YouTube, it's a property of any model whereby the profits of the host/platform maintainer are tightly linked to users spending as much time navigating the platform as possible (see also Facebook/Instagram/Pinterest infinite scroll psychology).