Maybe huge banks of tubes to power average-to-lower efficiency speakers are no longer as popular and acceptable as before. Seems high quality tube availability might be more limited and prices are significantly higher than before. Also, there is also sonic improvements in modern SS amps.
Personally, I’m not a fan of large banks of tubes or running so hot like space heaters.
Acora speakers has a lot of competition including the more recent Estelon speakers whose sound and form I favor more.

