RE: The Sound of Silence (er)

It looks very small. The bigger the supressor case is, the easier it is to contain as much gas as possible, and with that the noise. Another problem comes with automatic pistols/rifles when the breach opens, that lets also some noise out. I have seen solutions - like a modified Beretta used by special forces - that use a breach lock to prevent this. Revolvers are not optimal, because they tend to leak gas out of the cylinder gap.
For rifles, the good old bolt action works best in that context. Well, other manual repetition systems as well, I guess. But bolt action is still the gold standard for hunting and such things.

And of course the long wait and high cost are deliberate. Perhaps also because they know that you have no choice. I mean what could you do - complain? They just laugh at you and put your file to very bottom of the stack again. Same with the fee. You don't want to pay as much? Fine, then don't buy a supressor. That's how burocrathy works.