My point is there are no rules that it must be a tube amplifier.
The market clearly supports my point.
Audiofeil, Well said by one who sells both tubes and transistors.
Both of us point to the market to support our positions.
In the end, it is the user who makes the rules (not you and not me), and if their rules say 'no transistor amps' (perhaps because they don't care for the sound of transistors) then the speaker must match. You make an excellent example of the Apogee- not the best load for a tube amp. So in this case, no matter how much one loves that speaker, it will be an exercise in frustration if the match between the speaker and the amp was not sought first.