Actually, it is more like modern SS amps are sounding more like Tube amps. Modern tubes are every bit as good as the NOS stuff. frequently better. NOS tubes are a seriously expensive joke. More like a rip off.
Why don’t tube amps sound like tubes anymore?
When I hear the latest tube amps I’m more reminded of what a solid state amp sounds like than what I remember a tube amp once sounded like. I say that, with most tube amps I hear today, but not all. Gone seems to be the lush tones, warm glow and natural harmonics I used to hear. What I hear is more of a thoroughbred, faster, sharper sound when I listen to a modern tube design today. Then why use tubes?