[atoav]

What you say is true if we operate gear within specs. In guitar amplifiers when tubes are overdriven tubes, they still matter. Only in the past decade (circa) digital guitar amp simulations started to become sufficiently advanced to deliver convincing organic sounding results on that front, with DSP-based hardware that is suitable for the stage.

But if all you want is the sound of an overdriven tube amplifier, getting yourself an overdriven tube amplifier is still the least complex option technically, in terms of parts count, repairability, etc. It is a primitive technology, but it is also well known and works. It also has no menus, minimal settings and doesn't need firmware updates or registered accounts.

Personally I use both Class D and transistor based audio amplifiers for my musician life, since those are much lighter to carry for the same power and work for the type of sound I want.

If we talk Hifi unless they also want to overdrive the sound (they usually don't), tube amps are useless. The distortion figures of good transistor amps are much better, class D is making massive leaps in the recent years and has reached indistinguishable quality levels for a while now. These people should focus on room acoustics.