For internet crimes? Almost none in perpetuity. I’d think you’d need to go off the grid totally for a few years and come back without any reference to a prior life. For physical crime, my gut says quite a few people have avoided identification for decades until they were essentially caught by turning themselves in. Ted Kaczynski comes to mind, but there must be a few others.

Perfect OPSEC to me, means near total isolation from socialization. Not something most people are capable of.

If you’re a professional criminal of any kind you weigh the risks knowing that perfection is impossible. The government is a business with a monopoly on violence. The goal is to keep their ROI for catching you as low as possible. Every single man hour spent finding you is costing money and there’s a man upstairs who wants to see some results that reflect the money spent.

Once you understand that premise, it’s easy to understand the why and how criminals are caught. The ones who are caught are always the ones who don’t know when to fold. Always the ones not to cash in and retire.

The ones who get away with it, they fold they retire and society forgets about them and the ROI drops precipitously on catching them. Research statistics on cold cases.