So, why we certainly deviated a lot from that, it's still all connected. A lot even, at least IMO. Apart from what mbenigni mentioned, I think it's also simply because option paralysis is the best friend (or catalysator) of ear fatigue.
After listening to 463 IRs, you very likely won't be able to tell whether you prefer the 0.5in or 2.0in version anymore.
And it's not getting better with amps, not only because there's so many of them but especially as you don't run into their physical limitations anymore (see mbenigni). You can now have a Champ running clean at the same volume as a JC-120. And it might even sound great. So instead of one clean amp channel option there's now 50. Same thing, option paralysis -> no need to commit yourself to anything -> ear fatique -> no way to trust your ears anymore, even less so in case you never experienced what things were like using the real deal.
Add to this that there's tons of folks telling you this and another ton of folks telling you that. Possibly all creating great sounds of what they're using.
And add to this gazillions of gearfluencers telling you that unit XYZ is the final answer (to whatever it might be...) with the next unit to deliver the final answer to the same thing just being around the corner.
Back in my "formative years" I had one guitar, one amp, one or two dirt boxes and maybe a delay and a chorus pedal. So making final choices was a lot easier as there wasn't much to choose from, there's also been no YT or anything to teach me tricks or to tell me what to buy next. As a result I could only use what I had and simply had to trust my ears. I'm not saying it was any better, but making some decisions simply has been easier as you were forced by material limitations, something basically not existing anymore for the average guitar player in the western world.