This is true. A lot of pros also use backing tracks and many have been caught lip-syncing live shows as well. Just because someone else did it, doesn't make it a good idea.Not much different than using a load box on your amp , then going line out to solid state power amp in racks which alot of pros do .
Or tube preamp into a solid state power amps which alot of pros prefer as well.
Most gain or overdrive distortion people like in tube amps comes from the preamp and phase inverter tubes anyways unless you like dimming your old NMV Marshall's for the old school effect .
Anyway. My point stands. If you want a tube preamp and a SS power amp, then buy a Marshall AVT or something similar. If you want a SS preamp and tube power amp, then buy a Music Man or similar. If you want a fully SS amp, then buy a fully SS amp. Buying a tube amp and then replacing the tubes with SS circuitry is kinda like buying a Corvette and installing a 4 cylinder diesel engine into it. Why waste all that money upfront when you know you wanted something different?
Solid-state amps have their place, and when executed correctly, can be amazing works of art. But if that's the direction you wanted to go, you'd end up with a much better product if you bought an amp that was designed from the ground up to be a solid-state amp, rather than using one that was retrofitted with after-market components.
Now I've never actually heard one of these SS tube replacements in action, so I can't comment directly on the sound, though I'd be surprised if they sounded anywhere near as good and down right floored if they sounded any better than even the cheapest tubes currently available. Still, how many tubes would you have to go through to save money by replacing them with a SS solution versus just buying a SS amp in the first place? Tube amps are not cheap.