As atmasphere noted above, tubes produce harmonics (distortion) that most solid state gear does not. That distortion is pleasing to many, but not to all. It can also be overdone. I have a tube preamp (Cary SLP-05) and a solid state amp (Levinson 432). I like the "tubiness" of the Cary, but if I pair that with a tube amp the "tubiness" gets to be too much. In addition, my speakers are not very efficient and have a significant phase angle issue at low frequencies and I find they are better driven by a big SS amp. Also, I do not listen to much rock music, and, quite frankly, my system is not as good with that type of music as it is with jazz, folk, vocal, classical etc. My point - there is no right or wrong. It depends on the specific equipment, the type of music and personal tastes. And, as others have mentioned, tube rolling and tube adjustments, esp. in power amps, are not for everyone. It's nice to have options to tune the sound to your own particular tastes.
Why is solid state more popular when tubes are better?
Yes tubes are more involved and require periodic maintenance. Hybrid tube components need not apply, these are really solid state.
Tubes are better for multiple reasons and yet the world and the trade prefers solid state. Those rare audio shops that are geared toward stereo listening and serious connoisseurs tend to Focus more on tubes. Those in business who like to improve volumes tend to offer solid state. All the YouTube channels looking to improve their business tend to be solid state. Maybe because tubes require much more expertise to sell, and there's lesser and lesser to go around. Solid state is more of a fast food commodity.
Tubes are difficult for businesses due to all the maintenance and complexity so you see it less often. Much much easier to sell hybrids or solid state.