@asctim
I would bet though that if you took two different reasonably well designed speakers with the same baffle shape, same driver sizes and driver placements on the baffles, let’s say a 5" woofer and 1" dome tweeter on 16" x 7" baffle, they could be equalized and phase corrected to sound similar enough under blind testing that most typical listeners and even a lot of seasoned audiophiles would have a hard time distinguishing them.
I guess you could say the same about a lot of speakers put to a blind listening test.
Anyway, I don't think anyone is actually suggesting you can make 2 different speakers sound the same, only more similar in frequency response.
Whatever else, tonal balance is still a pretty important part of a speaker's sound, and it's good to know that adjustments can be made.
You might say that a flat pair of speakers in a flat room doesn't need tonal correction, but not everyone has that luxury.
I can recall an enthusiastic review for the diminutive Harbeth P3 where the reviewer felt it sounded remarkably similar to the vastly larger M40, just missing the (all important?) bottom octave.