In the real world, there's no reason to expect any of these limitations to exist. It makes more sense for backups to be cheap(ish) and taken every five minutes.
SPOILERS:
Altered Carbon also addresses the nightmare scenario of state vector theft very well; if the bad guys have a copy of your mind, they can torture you to death, over and over, forever. But in the real world, the precise mechanism of capture used in the book would be unlikely: if you thought you were about to be kidnapped, you'd just suicide, (using a explosive charge in your brain) and let one of your backups figure out what happened.