On the contrary, centralization can actually reduce the amount of content, at least for certain types. For instance, nearly any automobile will have a dedicated forum, and often these forums will provide some of the most helpful information, simply because they concentrate people around a specific subject. Whereas asking a question in one of the general automotive subreddits will typically yield poorer quality answers or will simply be lost in the noise. Thankfully reddit somewhat solved this problem w/ subreddits, since it's pretty common knowledge that the default subs are complete garbage, but youtube hasn't really done much about this. Sure, if someone made a video for your exact probem it is nice, but for finding specific information youtube is pretty poor.