It's the wait and hassle that kills suppressors, SRBs, SBS's, and whatnot. I don't worry about passing any background check, or even the government knowing what I own. The hassle of filling out the stuff, waiting, calling to see what's up, wondering if it was done right, keeping documentation safe and available, and the questions of "is this legal" here or there or if I move or travel, etc... OOOPS! - you're a felon now! (or at least you're out a pile of cash and time proving to a court "I didn't do it")
It's all manageable stuff, and many people do it, but I have better things to do and don't need to time suck or headaches. Remove all that and I'd grab one just for giggles.