> I think youtube has the potential to bring back DIY repair
This might depend on who you hang out with. I'm a tradesperson in the steel fabrication and construction industry, and I think a lot of people in this area have a propensity to want to fix and / or build pretty much everything themselves. From this perspective, with YouTube and online written guides, DIY repair is stronger than ever.
I recently tried to DIY repair a HP 12A toner cartridge. The Youtube videos in the DIY space are a wild mixture of shoddy camera work (bad quality cameras, bad lighting), language issues (I don't speak Russian nor Hindi) and, honestly, bad quality - there is one specific step involving a specialized tool that can be improvised by a screwdriver and a hammer, but all videos I found it simply went over this crucial step in a second without showing or explaining anything. And this is the case for many DIY videos.
A manufacturer-produced service manual or an iFixit guide however? Crystal clear photos that can be zoomed in, legible English (or at least you can copy and paste stuff to Google Translate!), links to "where to buy spare parts"...