That would be an argument for no law enforcement whatsoever: you can't stop all crime, so why even try to stop any crime. And it's just silly.
Because it's tax payer money. You don't spend tax payer money to beat a dead horse. Criminals use privacy coins like Monero, that cannot be surveilled. The argument for surveillance to catch criminals no longer holds up, as they now have tools that allow them to evade government control entirely.
In a perfect world, I would agree with legiteum but in this real world, I think that BlackHatCoiner is right, governments do everything for the sake of money, they don't do it to prevent crime and I'll prove it. Have a look at what happens in EU countries, they let violent refugees to come in our countries, do all the violence, steal from shops and so on, yet, they get all the best treatment in form of free money and free housing while us, taxpayers feed them. If governments wanted to prevent crime, they wouldn't let violent migrants in our countries. My friend lives in Spain and he tells me in Barcelona, phone thefts are so common that it's unimaginable but police does nothing. If they find a thief, they'll release him/her in a few minutes.