Doubting Sound Treatment ?

Bats piss. 
What? 
Oh, uh, what I mean is his majesty is a shining stream of golden light when all around is darkness.

any Serious DIY would fell own trees for lumber for frames, gin some 40 acre cotton and put mule skin over the foam from the backyard rubber tree...

The mighty SR duo shillers have surfaced from the mire, the other 4 will be along shortly, to combat any negatives on the HFT little snake oil thingies.

IMO room treatment is the most important aspect of having great sound. The most money for the buck upgrade . I use asc tube traps . Awesome customer care and they work with you like a architect does when  you are designing your room.
they sent you equipment to measure how ur room sounds from where u listen to music and review with you in real time and recommend changes. Amazing group of people. Shout out to Jordan . Prolly home made stuff are as good but I am sure there are quite a few of us who don’t want to do that .
asc or similar brand all the way . Sound treatment is  no 1 for getting good sound from your room. A music professor who is a piano player in the Cleveland orchestra came to my room and played the piano and was lost for words how good the room sounded . (My listening room is big and has a grand piano in it .) He was so excited that he wanted to have a live trio band play in my room and record it . Vote for investing in sound treatment , done right . 

any Serious DIY would fell own trees for lumber for frames, gin some 40 acre cotton and put mule skin over the foam from the backyard rubber tree...

You left out mine and refine the ore, smelt and cast, shape and sharpen, plant and grow. Evidently in your zeal to ridicule you neglected to consider there might be someone here capable of doing all that. Yeah. Put that in your pipe and smoke it.

DIY is Do It Yourself. A practical philosophy in no way associated with extremism. Let alone silly straw man "reasoning". Which you seem to have down to an art.