Not everyone does. I prefer my gun to go bang, not phuft. Plus I don't feel like spending the money on the tube, a threaded barrel, and the permit. I am indifferent toward those who desire one. They have their uses. My son has one, but it causes too many FTFs for me to want one.
That is how I feel about suppressors. They are cool but I don't have enough interest to spend all the money on obtaining one.