(New) Lawyer here. Don't know much about IP law, but my desk chair assumption is that the later technologies you mentioned aren't similar enough to break any patent. EG- Campy's ergo works differently than Shimano's STI so Campy isn't violating any IP. Whereas for Shimano to get a derailer to shift as good as Suntour's they had to copy Suntour's slant-parallelogram design.

Again, a desk chair assumption, but hopefully it'll get the conversation going.