Re: Better technology-so why are tube amps here ?
Feel is indistinguishably close, if configuration is right. Which requires either farfield IRs and a REALLY good Full Range Flat Response amp/speaker system (and not one of the cheap, common FRFR in name only ones), or playing into a higher wattage clean power amp into same speakers as the real amp, set to same volume. Most guitarists aren't used to playing guitar and hearing only the miked up studio sound...
A fair number of players prefer hybrids, using preamp models with a tube power amp into their favorite guitar speaker cab for the gig. Or sometimes a clean tube power amp with full amp models.
Line 6's Powercab+ is another stab at making a speaker system for modellers that feels like a real guitar speaker and cabinet (and particularly combines well with farfield IRs, and has a selection of similarly generated speaker models built in).
Really, the biggest remaining tradeoff in digital is inability to adjust amp behavior by swapping individual tubes, nevermind actual circuit mods, though Fractal Audio at least lets you tweak some of the key tube behaviors to taste and mix and match preamp and power amp designs. But you gain a lot of flexibility in having high quality EQs, studio-grade compressors, and other things that would otherwise require separate rack processors. Line 6 is a bit simpler, easier to use for some, with Sag, Bias, Bias X, Hum & Ripple in Helix giving you a LOT of control over the power amp behavior (and weirdly, a little Hum & Ripple have USEFUL effects in power amp tone for a lot of uses. Not something I expected at all!).
As far as why tubes? A lot of amp designers have experience designing them. Few have experience doing DSP coding, or with realtime circuit modeling (Fractal does NOT model by sampling a real amp, though you can do tone matching, which generates an IR that captures the difference in EQ and room response for the whole amp/speaker/mic config). Still, there are some amazing digital-only amps, like the Line 6 Litigator, Badonk & Doom, or several Fractal models (I've heard them, but haven't owned Fractal & can't recall specific names). Fractal Audio has also been involved in prototyping a digital version of an amp before building a physical model, for Carol-Ann amps!
I'm glad new amps are being made by the likes of Revv & Grammatico, and that they are making deals to get their stuff into modellers as an advertising channel for the physical amp! (Yes, people do sometimes buy their favorite model in a real tube amp. Great way to trial amps, even for people who want the ease of repair of a tube amp for live use.
Or people like Friedman and Fryette, who seem to have some antipathy for modelers (though again, I hear a fair number of people who buy HBE-100s or the smaller variants because of the Axe-FX & Helix models of it), I'd hate to see them quit the field, even if I never actually play one of their physical amps. I don't think the Synergy amps with official preamp modules from numerous different companies would have happened if it weren't for modelers, and there's a number of guitarists I like who don't care for modelers who are switching to Synergy. I don't agree with their conclusions on digital vs tubes, but I'm happy they have an option they like!
The dynamics really are there now. If you want the exact same response as a particular tube amp, you need it set to same volume (set model's master to same master settings as your physical amp, use a power amp that can provide same power, which in case of solid state may mean you need 2 or more times the power, particularly if the amp is rated for a lower impedance speaker than your tube amp). A lot of people try to use the modeler's ability to record same tone at lower volume, and are surprised it doesn't FEEL the same doing that. Given volume impacts things like string vibration, it's not shocking that it feels different if you let a key factor change...