You're right. In 10-20 years time the AxeFX II will still sound just as good as it does today. In fact, if someone wanted to never again updated their firmware and stick with 17.04, they would have a rack that could give a lifetime of professional-tones plus a suite of studio-grade effects that would never sound out of date.
Contrast this with your computer, which after a couple of years won't run the latest software. Or your smartphone that after a few years won't run the latest apps, OS and at some point won't even connect to a network. Or a video game that may look fantastic today, but in a few years will look dated and cheesy.
I've been a fan of the AxeFX for years, having the Ultra and then the II. I still buy pedals and maintain a full "traditional" pedalboard. In fact, just a few days ago I finally bought the amp of my dreams (Tone King Sky King). As powerful as the Axe is, sometimes I just want to twist a couple of knobs and have a great tone. I don't think the Sky King is capable of a bad tone because it is designed from the ground up, with a real speaker, quality cabinet and great components. You get a fantastic tone just by virtue of having the amp on. A few twists of the knobs or flips of the switches gets you variations on that solid foundation tone.
The AxeFX is designed for a guitarist as well as a dedicated studio engineer. It's depth is vast as well as it's flexibility nearly limitless. A lot of players find it to be a simpler solution, especially those who have had to haul heavy stacks to gigs, deal with cable capacitance, temperamental pedals, changing tubes, having to attenuate to get their tones at levels that won't get the police called. Then again, with the AxeFX you need to consider monitors (which can cost more than the AxeFX itself), MIDI controllers, MIDI programming (if you're not using an MFC) and tweaking. It is quite possible to make the AxeFX sound terrible. The AxeFX gives you a lot of rope, but enough to hang yourself if you don't know what you're doing. I've been caught into the trap of obsessively tweaking a patch to the point where I forget to just practice. At the end of the day, you're content in the knowledge that you're getting a facsimile of a real, perfectly-mic'd, amp's tone.....but not the real amp itself. Mind you, it's a VERY good facsimile...the bleeding edge of technology, but not the real thing. This bothers some people, others are happy to eat their Matrix steak ;-)
The question is what matters more to the player?