perhaps it is obvious to most here, but for those less knowledgeable, let’s review why the world isn’t populated with home and room friendly $1500 a pair speakers at 95 db/w/m efficiency that sound just wonderful...
when you make a speaker more and more efficient, you use lightweight transducers or horn shaped ’magnifiers’ to get the additional output or ’loudness’ -- but you get it primarily in the midband and lower treble... so you then need to deal with the lack of bass, and the lightweight transducers being less stiff and hard to control once they are moving...
so then, to get better bass, you need a big big cabinet (that’s why many ’good’, e.g. well balanced top to bottom speakers are very very large)... many also try cabinet porting, but then there are difficult port issues to deal with when alot of air is moving on bass passages, so then you damp the port to control that, but then you lose efficiency again... doh!!!
lighter transducers can be solved with high tech materials, but you still need power to move the voice coils via magnet structures, and you tend to want smaller lighter magnet structures but you use those and they often overshoot... thus more distortion, especially on complex music... doh...
horn magnifiers have their own type of wave propogation distortion, highlighting imbalances in frequency response of the driver they are magnifying... which then in turn take a lot of skill and cost to tune properly, as room conditions in home applications can vary considerably
due to the above, it is very very very hard to build a well integrated top of bottom speaker that is high efficiency and of a reasonable size, and has bass response we want ... and this is why even good high efficiency speakers tend to sound a little more ’peaky’/’ragged’ than counterparts of equal cost and quality but lower efficiency
so all this is a long way of saying, let’s understand what the industry has been dealing with here -- it is basically a tough physics problem -- and with cheaper clean amplification becoming available over time with solid state amps, this is why the industry took the route of reducing efficiency to get a more ’flat’ and bass impactful sound out of domesticated speakers.... and we can of course argue speaker makers went too far off course in that direction as well
so if it were so easy to make super great sounding high efficiency speakers that can satisfy us and look passable in our homes, easily driven by sweetie pie 8 wpc single ended 300b amps -- they would be flooding the market, and we would all have them...