I foresee the cycle of innovation will be: 1) offline (PAST) 2) cloud-hosted (PRESENT) 3) cloud hosted but with full offline support (FUTURE) This way we'll have the best of both worlds.
What's good about cloud hosted POS you ask? Well they do update easily. So you are not stuck with the same system with 90s UIs.
Also by upgrading faster and being connected to the internet the POS is able to interface with external systems. Currently 99% of restaurants use a separate tablet for each online delivery service (deliveroo justeat foodpanda...).