Most rooms don’t need acoustical treatment.


Why?  Because acoustical treatments presented are in virtually empty rooms. Unrealistic.

my rooms have furniture and clutter.  These rooms don’t really have a need for treatment.  It’s snake oil, voodoo science.  
So why is accoustical panels gonna help?  No one can answer this, most have no clue.
jumia
Lamps on end tables reduce room modes.

Sums up the understanding of acoustic treatment 
some are commenting on.
Pretending acoustic treatments universally do not help is to assume that the amount of clutter, rugs, drapes, blinds, bookshelves, upholstery, art on the walls, etc. is uniform in every room.  If you have "enough decor" to not require any extra treatments, then great - but rest-assured there are many rooms that will in fact benefit. You can have someone clap from each of your speaker positions, and if you hear reverberation or sound decay from your listening position, then you might want to consider treatments, whether those treatments are "decor" or specific acoustic treatments. If you do not add treatment, then you can expect that the sound leaving your speakers will be subject to the same "added color" that you heard around the test clap.  
I dont think "normal" rooms have 4 inch thick bass traps in the corners which DOES help tremendously if you value great non boom bass. Other stuff is great as well, one of the least snake oil things in this hobby which there is plenty of. 
@dekay ...as long as you keep all your remotes on your belt in that space you're good to go....;)
"my rooms have furniture and clutter."

Why do you assume that my room is cluttered?

(It is not)