Why is solid state more popular when tubes are better?

Tube amps are LOW FI , not HIFI, since 50 years

Talking about "fidelity" : tube technology is inferior to well designed SS technology, and deprecated since 50 years

Tube tech provide : high distorsion, high noise, high heat, low power, low reliability, high cost, non linear frequency response... Everything is worst in a tube amp (and please don't ask about even distorsion harmonics : these harmonics, as their name tell it : are relevant to distorsion... and there should be no audible distorsion at all in Hifi : so even harmonics are out of scope).

The only domain where tube is still superior is : LOW FI : mainly for guitar amps where high distorsion with majority of even harmonics and frequency response non-linearities are qualities, and high noise is not a problem, as well as low power on 15'' high efficiency guitar speakers.

Emergingsoul, I'd say you struck a nerve here! How dare you challenge someone's core believe! I picture in my mind how it would have been in the old west had there been audio equipment back then. The shootout at the O.K. Coral would have definitely been between Tubey Tobias and Solid State Sam! Now, where do you stand on interconnects? Watch your step!

This is very much a 'first world problems' discussion, but my pennyworth is from the perspective of someone who owns both S/S and - very recently - a valve amplifier. I've always had S/S, from original Quad 303 through (currently) Mark Levinson 331 and (my favourite) Michell/Trichord Alecto II monoblocs. All lovely stuff and I've never felt short-changed in the music department, but I've always been curious about just what difference (if any) a good valve setup could make.

The first valve amp I really listened to was an Octave v80SE, at the dealer from whom I was buying some Martin Logan speakers. Was most impressed but, in a dealer system, hard to tell what was making the difference. But it whetted my appetite – valve-curious, if you like… 

A couple of months ago, having missed out on a great deal on an ARC i50, I got the offer of an Octave v110SE with the add-on SBB capacitor bank, at price which, had I turned it down, I'd have spent the rest of my life kicking myself about.

So, inserting it in place of the Arcam pre and Alecto power amps in my system, and I'm absolutely delighted: there's an inherent musicality, subtlety and depth to the output that was (and remains) immensely appealing. That's not to knock the previous system, but just that the Octave provides an overall more satisfying experience, and I find myself listening to music even more than before, and finding new things to hear in familiar recordings. 

The downside of course is warm-up time - I've been listening for about 40 minutes this morning, and the thing is only just waking up and getting into its groove.

Then there is the cost of replacement valves, but you factor that into the purchase anyway - I'm actually pre-emptively purchasing a new set of KT150s against the time when the in-channel supplies of Russian manufacture dry up altogether.

I'm also discovering the delights of 'tube rolling', which adds yet another geek dimension to a thoroughly OCD hobby… :-)

seems as if you answered your own question and the premise is based on preference.  

like many things- it's complicated.  each amplification method has its set of pros and cons.  to say which is better requires a lot of qualification.  

I built a Pass First Watt F5 and thought it sounded great. Then I built a 6V6 SE amp. Each cost me about $400 to build. The F5 now sits on a shelf disconnected from everything. Solid state sounds like a wet blanket in comparison. I am also a lifelong guitar player and solid state guitar amps sound pretty much like many solid state stereo amps - no harmonics, little dynamic range.  Dull.  Boring.  What Atmasphere says about his class D design is very interesting and I don't doubt him at all.  Looking forward to when something like it can be built by hobbyists like me.