Too often people try to rationalize things they don't approve of by saying it "will never blah blah blah completely" Whether it be Encryption in PS radio or the War on Terror every effort taken is just that, an effort. Add up the efforts and you build a more complete deterrant.
Nobody expects encryption "will stop crime" not even the police chief who pushed for it. Hardly ANY criminal is listening to a scanner in the first place, but depending on locale, some are. If you deter one crime by use of encryption over the lifetime of the radio system, then encryption works. Same story for the war on terror (not to get off topic but to continue the thought). Of course putting an extra cop on a train or bus station isn't going to totally eliminate the threat. If a terrorist strapped explosives to his chest and walked into a crowded train station, that extra cop just might see him and prevent a problem. Even if 1000 other bombers succeeded, preventing one made the system work.
Get over whining about encryption, as was stated before, none of us scanner monitors likes it, but those radio systems are not designed for your entertainment. Just because you paid taxes that contributed to the implementation of the system doesn't give you rights to ownership.