If it can run on your PC when copy-protected, it means at some point the CPU executed the right instructions, so a crack is always possible to create. It's just a matter of how much effort and time is it to reverse-engineer it. You cannot copy-protect software indefinitely.
I remember feeling cool as fuck as a teenager because I cracked GTA 3 by dumping the live memory of the binary post decryption. Of course it's been 25 years, so the status quo has improved by a lot and god knows how many man-years and kWh are wasted on copy protection.