There are probably, what, 1000 or more unique amps that have been/are on the market at some point or another. Many of those amps aren't really that different, sometimes just using a different type of tube etc which can be easily swapped in the Axe.
In other cases, there is surely enough variety as is to cover pretty much the full sonic spectrum. Take Fender amps for example, between the tweeds, the black faces, the "fat" versions, the silverface versions, all those classic tones are there. I don't think every circuit of every amp they've ever produce is required to produce some nice Fender tones.
Eventually you can get to diminishing gains, as lets say there were 500 amp models. Who's got time to check out even half those ? I honestly haven't spent enough time with even half the models as is to feel I've really got to know some of them.
Been spending time on the JCM800, the #34, the Brit Silver, the HBE versions, the Atomica, etc and honestly haven't even gotten a chance yet to really dig around with the CCV's, or the Fractal Hot Rod or others.
Its like if you owned 500 guitars, you'd likely never touch most of them. Now I don't think one can own too many guitars lol, but there does become a practical limit of if your just having something to have it, or because you actually will put it to use
