If only it was that simple, lol.
I “strongly “ suspect that the main reason that Alon doesn’t exhibit his speakers with tube gear, except for the big CAT’s, which are basically brutes in the tube world, is due to the fact that his designs are far too difficult a load for perhaps all other tube amps to drive ( and naturally, he knows this!) Adding more cabinets to his design would only serve to increase this problem.
IMHO, most speaker designers know what works well with their designs, as far as upstream gear is concerned...and then they leave it to the dealer to disseminate that information....
I actually think it is that simple. Have chatted with former Magico employees who went to other audio companies and he just likes SS. If you have been to Brooks Berdan that have several rooms that were all driven by Jadis PP and tube front ends (may have changed it has been a while since I visited). While a little laid back to me it sounded much better compared to many Magicos I have heard using the best SS equivalents.
Even with Wilson which is not my cup o tea, it has always sounded much better to many with VTL;s and AR gear vs a SS counterpart.