I understand how you can reach that conclusion, and don't necessarily disagree (I bought a different amp in a similar price bracket). And yes, we are, though I thought the added context of speaker sensitivity, distortion spectra, etc. was reasonable.
Re. the first, Amir mentioned a typical speaker being 82db sensitive. Let's contrast that with a horn-loaded system with a sensitivity of 102db (yes, they exist). Next, let's pick a listening level, say 105db (arbitrary, but there are frequent discussions on DIY tube forums re. power needed to produce reasonable volume in systems of "x" sensitivity, and in the world of limited output power, 105db at max amp power is reasonable- though not for all, and there are good reasons that might be true).
To produce our 105db per speaker, the horn system needs 2 watts (and will almost always be operating off the chart to the left (X axis) of Amir's curves on the distortion measurement he added (300mW) at normal listening levels). The "typical" (though I would never buy one that sensitive) would require 200 watts. If you wanted, on huge transients, to hit 116db, it would be 25 W and 2510 W, respectfully. When choosing amplifiers to pair with speakers, it really is "horses for courses."
BTW, you might be shocked re. how inefficient speakers are in converting electrical power from the amplifier into acoustic power. For the 82 db speaker it is 0.1%. For the very, very sensitive horn speaker it is 10%. For speakers that I would consider more typical and consider purchasing, say 89 db, it is 0.5%.
Bill