It's digital modeling, so it's not a solid-state vs tube argument. "Solid state" is a physical circuit made of transistorized components, PC boards, with op amps and diodes replacing tubes and point to point circuitry. That's different from digital modeling where the modeling is trying to emulate tubes and the point to point circuit, and remove any actual physical circuitry from the equation.
Anyone who's stood in front of a tube amp pushing air and a modeled amp pushing air can perceive the difference. In particular, a tube amp sounds like a really nice amp, with punch and dynamics. A digital model sounds like a recording of a nice amp, even if you run it through a tube power amplifier. I'd rather put a microphone in front of an actual tube amp than a digital modeled sound coming through a digital power amp and 'custom designed for digital' speaker. Putting a mic that close to an amp is the same as putting your ear there - it starts to expose all the details of what's different.
Fender would have to tread carefully to enter into direct competition with Marshall, VOX and other brands, selling Fender versions of the same amps. Third parties have done that, in an equal opportunity plagiaristic way, but the big names try to avoid that. Marshall is based on a Fender Bassman, but Fender has never made an "M-flavored British Bassman" in response (that I'm aware of), at least not so overtly to hint they are copying something. I think they would be wiser to stick to their brand and push their own brand.