Good point. Given most economic gun crimes start with the gun presented and the victim complying, an expensive suppressor probably doesn't enter into the mind of the robber. They don't particularly care about such - any old gun would do.
Crimes of passion - having a silencer is a nonissue. They are driven by the intent and then go for the weapon. Having a silencer doesn't seem to fit into the interview studies of those who committed such crimes.
Deliberate assassinations or drive bys? Maybe in the extremely rare first case. Drive-bys probably want to make a statement by the pray and spray nature of the gun fire.
The biggest reason criminals don't use a suppressor
is that they are cumbersome. Imagine your glock with a 12" barrel, it doesn't exactly fit in the old waist band or in the small of your back very well, does it?
In several European countries, suppressors are required
for hunting with a high powered rifle.
The proper term is suppressor, the device does not completely silence the report of any firearm larger than a pellet gun. Using the word silencer simply feeds the ignorance and hysteria of the uneducated anti gun crowd.
Just like calling your favorite AR an assault weapon.