Here is an example of a decent speaker. The B&W 804D3.
Clearly you can measure and position till you are blue in the face but the fact is that the speaker is some 8dB higher in the 100Hz range than the presence region of 2k. Then the response is bumped up in the brilliance region to get that airy response from it. Not taking that into account, the measurements will be all over the place depending on where it is in the room with all the modes playing with the speaker and even if you did find the optimal spot, there is still the basic characteristic of the speaker itself that is still some 8dB higher in the bass over the mids because the designers probably tuned it to be that way.
