The big difference here is that by the time the 2080 had saturated the market, you could regularly find a 1080 for ~$300 (I paid $275 for an EVGA B-stock model).

Whereas today, with the 5000 series in the market for quite a while already, a 4080 is still well over MSRP

Back in the day 1080 was top of the line. For couple of generations now it's xx90 lineup.

You could say that there was Titan but in practice they were not seriously considered. At least for gaming.