I have big A$$ Tannoys In my medium sized listening area and they sound great. Little to no room treatments to speak of, but room is well balanced with furniture and acutraments. Speakers towed In quite heavily, and they are concentric drivers, so they project the sound out of the box and to my ears quite well.
Lose weight or buy better fitting pants
We talk about fixing the room constantly but couldn't the size and shape of the speakers be the problem?
I realize it is not economically feasible for manufacturers, but this could possibly relate to dyi folks.
For example a long narrow room with low ceilings would have speakers proportionate to the dimensions of the room. Smaller tweeters, drivers, with an enclosure mimicking the room. You would design the speakers to fit the room, instead of fixing the room. Start with the room as a extra enclosure. Make sense?