Unfortunately they won’t last for years to come if you don’t update the software. At which point 3D Touch and force touch will be gone from both devices.
Apple struck a decent compromise with iOS where hard pressing like 3D Touch registers it in the system nearly instantly. watchOS though goes to redo-ing some UI behavior present since version 1.0.
To clarify I run latest OS, just saw a lot of potential in a feature I used countless time. but had friends even yesterday discover it on an 11. Sam folks are longtime iPhone users