For starters,
Less electricity.
Less heat.
Less maintenance.
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.