Most solid state amps are designed to work with typical all SS pre-amps/systems, not higher out impedance tube pre-amps.
I think its that simple.
With ongoing popularity of tube gear in high end audio, some lines are designed with higher input imepdance to work well with tube pre-amps as well. But it is a niche market so still not as common as would be the case otherwise.
Impedance matching is important for optimal sound quality,but many might not notice otherwise or care. Plus practically its really only a significant issue when a higher out impedance tube pre-amp is involved.
I think its that simple.
With ongoing popularity of tube gear in high end audio, some lines are designed with higher input imepdance to work well with tube pre-amps as well. But it is a niche market so still not as common as would be the case otherwise.
Impedance matching is important for optimal sound quality,but many might not notice otherwise or care. Plus practically its really only a significant issue when a higher out impedance tube pre-amp is involved.