We should reject hard-to-drive speakers more often

Interesting subject. I know of a few a'phile friends who bought speakers without first contemplating what amp will work with them. These folk either no longer own the speaker, or they have bought high powered ( and usually low SQ) ss amps to drive their speakers. Then we have the guy who bought a SET amp with 8 watts/ch hoping to drive his Wilson Alexia's. Disappointment might as well have been his name!

Problem is that unless one is listening to basically horn based speakers, then the requirement for upstream power is going to be factor. But, I do agree with you, the needs of a speaker like the YG's, or the aforementioned Apogee's, should be a turn-off to most hobbyists.

MBL is an awesome speaker.  One of the most serious speakers in the world.  MBL can be brutally revealing and difficult to drive.  Bring your A game or keep looking.  I've heard Convergent amps drive the heck out of them, but a lot of really good amps will struggle at some point to keep their composure.   

While I don’t disagree but people want small speakers and deep bass so that in turn makes them hard to drive. They often wire multiple bass drivers in parallel  which drops the impedance too  

I have owned 86db speakers and 91db speakers and don’t notice much difference but use a pretty powerful amp at 450 watts a channel. I am in the camp of but the biggest speaker you can afford and bigger is always better lol. 

HTD speakers matter! Come on it’s 2023. I thought that we were supposed to get over this back in the 60s when we had all those speaker riots. 

I have never liked an efficient loudspeaker/set amp combo.

What is an efficient loudspeaker anyway? 100+db? 95+db? I’m not sure if I ever have had a speaker > 90db, but I have had some 85db stand mount speakers driven by 1000 watt monos that sounded fantastic, most of my speaker/amp combos were around 88db driven by 250-350 watt monoblocks