Rolf, the issue is not what cool stuff can inventive people come up with... and perhaps catch on... Gordon Isco was foiling his hobie 18 a long long time ago... The issue is what drives groups of people to go racing... and the answer is... Its the race.
The T is a particularly bad example of the gear driving anything. The class had a trials in Miami to test out course configs and new gear by way of sailplans (spin, non spin and modificiations). Everybody brought their cool stuff. The trend back then was to push for trapazoid courses to max fan appeal.... eg. the blast reach legs (now part of the AC racing). Booth and Forbes showed that the square top T was faster around the Trapazoid course then the spin boats. Smyth was doing the spin tornado at the trials having done lots of worrels by then ... My comment at the bar to forbes was... wow... every rec sailor on the planet wants a cat with a spin... Why would the Olympics Class not go that way. ... His answer... well.. it's about the Olympics.
Indeed, it was some members of the class.... because the actual class rank and file voted the spin down... and then magic happened and ISAF got their way with the T class spinoff and the olympic sailors were going to the spin for the Olympics. The rank and file adjusted their opinion and voted to go along.

The event most definitely drove the equipment.
(The Worrel was conceived and run as non stop on Hobie 16s... and then bigger better faster took over)

Jake makes a good point about the Trifoiler and the Rave. They remained cool toys and not racers... My suggestion is that there were no races that people wanted to (or could do) do on these boats to make them viable.

For a current example... take a look at the single handed with spin class. Builders have generated the Nacra 17 and then the Nacra F17. the Marstrom 18 (A class with spin) and the F16 single hander.. There is no event that motivates sailors to race and these boats don't really have a class. Instead the Hobie 17 and the A class chug along. The A class incorporates new technology daily but its the racing that keeps the interest up... not the technology.