The Titans ran consumer hardware, but professional firmware. That when paired with the creator drivers (which don’t get the game optimizations) led to a weird hybrid state which left the cards existing half way between both. But you could use the game ready drivers to get the same or slightly better performance than the 80 series of that same generation, but at a price that made it not worth it for all but the FPS chasers who needed the fastest price be damned.Yes and no. The 90/90 Ti is clearly also the rebrand of the 80 Ti tier and what it used to be with a price hike, but also sort of a hybrid between that and what used to be Titan with the 24GB. That said, historically, Titans had functionality that was gimped on GeForce cards and their own drivers to enable those workloads. That might not be the case anymore I'm not sure, but at release there were definitely things the RTX Titan still outperformed the 3090 on because of that. To just blanket say 90's are Titans....I don't know.
What I do know is that historically, the 80 Ti cards were the top end GeForce cards of a given gen, and that simply isn't true anymore since the 30-series, and the 40-series has yet to even have one over a year later.