Forgive me, but I strensuosly disagree. Mass produced high performance full squidge didn't exist until the Renault F1 designed GiantnNRS system came along on the original XtC.
You mean the Horst Link system they used? Like FSRs, AMPs and GT LTSs among others which pre-date the NRS considerably?
Anyway I think '96-97 is a great cutoff point, take a bike from say '95 and one from '98 and compare them, absolutely worlds apart. Its arbitrary but it is a point where design shifted big time market wide.
Look at vintage motocross racing; its a bit like the Pre-1975 cutoff in vintage MX, the long travel bikes in 1975-76 changed the game hugely compared to everything up to '74. The example from vintage MX though is as the sport matures the line moves, and there will be support for later stuff as it goes from being simply outdated to being vintage.
Hence in vintage MX there are now classes in pre-60, pre-65, pre-70 (and evolutionary terms they're slow, weird and less reliable, a lot like early mountainbikes), then pre-75 representing the boom era of MX where there was huge tech change and massive uptake of the sport, pre-80 representing when travel got longer and bikes got a lot faster (much like say '98 onwards for us), and now we have people racing pre-85, pre-90 and soon pre-95 as time marches on and people want to relive their golden days.
Funnily enough there is a lot of lament in the pre-75 scene for the booming popularity of the pre-80 and evolution period classes...the same might happen here, in a few years there might be bulk early 2000s tragics fighting over M960 and Giant NRSs.
Probably the key difference is we don't have much organised vintage racing yet...