As one who has correctly treated my room, I can also point out the importance of the room.
BUT, the speaker is also extremely important.
Sorry, but no matter how good one's room is, if a speaker is lacking detail, transient response, accurate timbre, is inherently colored, NO AMOUNT of room treatment is going to correct for that.
I have heard plenty of very high end speakers, in average sounding rooms, sound better than lesser speakers in well treated rooms.
For example, I have heard Von Schweikerrt VR 55 mkII ($65K). in a typical living room sort of setting, sound substantially better than a pair of $14K Sonus Faber (not sure the model) in a professionally treated room.
The Von Schweikert's had better attack and decay, had better transient response, had a bigger, deeper, more detailed soundstage, were more neutral, timbre was better.
Those things are inherent in the speakers themselves, and no amount of room treatment will get a lesser speaker, to do what it is not capable of doing.