Have you ever listened to decent monitors in an acoustically dead room? The monitors sound great. The room sounds like ass but you're not listening to the room, you're listening to music. Music, when mixed, is mixed in a room with minimal acoustic coloration. Blackbird studio C minimal? No. But minimal.

The argument you're trying to make is "different speakers need different treatments" but with omnidirectional speakers, the treatment is tantamount while with directional speakers, the treatment is bonus. After all, they don't splash crap all over the walls on purpose. All of your arguments come down to that - "in many cases sound better" is happy hand-wavey subjective observation that has nothing to do with acoustics.

Headphones close-couple. Everything with a volume under a cubic inch is close-coupled below 8,000 Hz. Size and shape has fuckall to do with it; anything below mouse farts energizes the entire volume.

I am saying that from an acoustic standpoint - as in, from a repeatable, testable, empirical standpoint - speakers in an anechoic chamber will reproduce audio better than speakers not in an anechoic chamber. That's why speakers are tested in anechoic chambers. That's why speakers are measured in anechoic chambers. You're right - speakers are not enjoyed in anechoic chambers but the fact remains: a speaker that deliberately sprays the back wall should specify how far in both directions it should be from the walls, what those walls should be made out of, and where you should be standing (in two dimensions) in order to properly enjoy the speakers.

A directional loudspeaker you need only listen to.

Amar Bose was hella more famous than Linkwitz or Toole. He made a lot more money. He was also a fucking idiot who built everything out of 2 1/4" paper cones. That doesn't make paper cones genius. Go ahead and appeal to authority - I'll appeal to every other designer that didn't make trashcans.

Look - there was a time I patched my stereo system through a Quadraverb II. It made things nice'n'roomy. Right now I've got an Eclipse DSP in my car that allows me to play bullshit stadium/club/church/whatever games with my music. But I'm not fooling myself about what I'm doing - I'm coloring the shit out of the sound. Works sometimes. Not so much other times. Pretty goddamn geeky.

Also, a substantially more controlled, more purist, more repeatable and more defensible method of adding "early reflections" in order to improve the sound.