Between the many amp models present in the axefx, and the many parameters, you kinda can already design your own amp. I think it would be great to have a user interface that displayed the actual schematic layout and component values, all of which are completely editable and 100% accurate to the physical world without the limitations of the physical world. What a wonderfully disturbing rabbit hole that would be. "Exmachina", anyone?
But the fact is digital technology is here to stay; every market supports it. What markets support tube technology? Tube stuff, guitar amp stuff in general, is highly specialized and with specialization comes exclusivity. I still see a `63 split window `vette on occasion, and I can tell you it is something special to drive. But it really can't compete with a new one; even the radio is not as good. I have a wonderful old marshall. It is hand wired, has high dollar coupling caps, nos tubes, tweaked out and everything. I love it but just like that old 'vette, it is a one trick pony. It is special - but only from a very narrow perspective. It comes with a lot baggage. The tone is shapeable within a very narrow range, it is always a marshall. You can make it do clean but it is never a fender. It is loud. Loud is a part of the sound and feel of the amp. If you take that away you kill the amp - it loses the a part of the thing that makes it alive. I could go on and on...
The axefx, on the other hand, can actually take the character of that amp and provide you with incredible control over these characteristics. You can compensate for what you lose when the volume is not as loud. You can actually enhance the characteristics that make an amp special. And with the flick of a switch, you can do that with a Ferrari, ...I mean a blond fender. It ain't heavy and it don't get hot. It already sounds and feels as good as that special marshall, to my ears, and it seems to be getting better monthly. It will continue to get even better.
Tube amps will become costly nostalgic antiquities and when we occasionally plug into them, we will be blown away at the power of volume and amazed at the lack control and practicality, ...just like that wonderful old 'vette. It is only a matter of time boys and girls. My humble opinion and all...