Some of the nicest ones are. Most are not.

GPS isn't itself useful. That lets the bike know where it is, which is meaningless without the ability to communicate that to the outside world. That requires a cell connection and active subscription, which costs money. Most bikes do not have this ability.

You can out an apple tag in them. Most of the theft recovery stories I’ve heard about involve the Apple tag. A GPS + cell networker transmitter would help, but the power requirements would probably make it infeasible. Apple tags work great, although thieves are getting iPhones of their own to figure out if the bike has one via the anti stalking feature.

Also, trying to re-get your bike from an encampment after you tracked it down is dangerous, and the police might not have time to help you get your property back (although I’ve heard a success story here as well).