That statement seems to be incorrect.
1) Amps do have EOL (or a least end of support from the manufacturer, end of tube life, end of some component life, etc)
2) Amps do not produce "unique" sounds; they can all be accurately modeled, and you would not differentiate them on a recording.
3) Their desirable sound will only last until the tubes worn out or get microphonic, the bias adjustment is gone, or the amp is broken
It will sound exactly like a 1952 Fender Twin in good condition will sound 50 years from now. Why would that be undesirable? The tone of a modeler doesn't degrade with time. The Axe-FX III has reached a point of perfection that leaves no room for dissatisfaction on the tone that you can achieve (ulness you have some ridiculous whim