COD:BO7's single-player uses dedicated servers. Terrible, yes, but that's as foolproof as it gets when it comes to piracy. They also probably did this to combat all the 'services' offering to unlock camos/cosmetics that you'd normally have to grind for; players would give someone their credentials (probably stolen later and sold to cheaters) and the person on the other side would then use a hacked client to trick the backend into thinking they completed all the challenges. With a server-side campaign, that probably got much more time consuming, I reckon.

Every game separately encrypted then compressed into solid archives. Pressed in a way every game lands on different precise height of CD, padded before compression if necessary so it takes enough space on CD. Separate machine burning tiny holes in CD from the back, but not so tiny that CIRC could fixes them. At least one hole per file.

Install locates the damage and gives you code encoding locations. Over the phone You receive ECC code. No more magic keygens, pirates have to distribute whole multi megabyte games.

there isn't a market for gamers buying games on CDs these days, so it's not really a problem that needs to be solved