> Building a comment system at the scale of YouTube along with creating a new identity system for it is likely not a small amount of work. I'd guess that they're still working on making it a reality.
Well , Youtube had all these things before the G+ insanity.
I don't really see how that's relevant; you're talking about a system from years ago. It's not like they could easily just go back to that, especially with so many comments stored in the new system.
Furthermore, the G+-powered comments section brought about many new features that I imagine they wouldn't want to get rid of, like threaded replies, text formatting, improved ranking and spam detection, moderation tools, and probably more.
Well , Youtube had all these things before the G+ insanity.