We should reject hard-to-drive speakers more often

Why?  Choosing speakers to buy / avoid based on efficiency is like choosing a new car based on a sole factor such as weight or acceleration.  I am not sure if I need to tell you it doesn't make sense.  ATC drivers/speakers are one of the most inefficient speakers (around 85dB/w/m) but, with due amplification, I am pretty sure that I do not need to tell you how good they are.

In the opening, the OP said out loud that "We need to reject hard-to-drive speakers as being Hi-Fi". Now the tone was evolved to "... It's fine with me if you buy a car that gets 10 MPG. What I disagree with is the awe and bragging rights associated with that..." and followed by "No, your car is not better to ride in or more exclusive than high MPG Cars just because it's low MPG."

In reality, in the hi-fi world, I think very few audiophiles (if there is any) will procure speakers just because it's low efficiency. The speaker designed to have lower efficiency has its good reason. Take ATC speaker/driver as an example, if one desires a good low frequency extension out of a small-to-medium sealed enclosure (which I prefer) design speaker with a given size of driver, efficiency has to be sacrificed. Manufactures/designers could achieve higher efficiency by utilizing vented enclosure like tube/flat ports, lighter material for moving parts, horns, etc., but the sound reproduced from those designs may not suit some audiophiles' taste. In addition, quoted from the ATC designer, "The low mass parts are often not suited to the forces and resonances generated when reproducing audio at high SPLs and the structures that behave well at low levels can become unstable.  When the driver was reinforced for its stability and high internal damping, reduced sensitivity is unfortunately a trade-off.

@atmasphere  what about large multi-driver full range speakers that are really hard to drive? They don’t get the Murphy that a smaller speaker does for low efficiency.

Thx for the comment.  You got me to think a bit while longer but it is definitely worthwhile. I think the answer to that is the so-called Hoffman’s Iron Law that someone more knowledgeable has pointed out. It states that the speaker designer could pick two parameters out of the bass extension, sensitivity, or small cabinet size in any given design, but in doing so it will compromise the third.

So extending that notion to your question, you can have efficient larger floorstander containing multiple, larger drivers in combination with cabinet designs to give great bass, small speakers with great bass and low sensitivity that I have craved for, or small highly sensitive speakers that can’t reproduce bass well.