concern: like every system that we think of as cloud software, the 'cloud platform integration' half of it never gets open sourced
same as like, aws extending mysql and postgres to provide RDS features -- they don't open source those pieces, so 'stock oss' DBs don't have fancy RDS features like backup + restore
with kube, platform-integrated components like network, ingress + storage 1) require custom work on each cloud, so new features won't be available on all clouds at the same time.
But also 2) that means some components, ingress specifically, have different interfaces on different clouds when they do finally get implemented.
Sure each provider does things differently, but they still work with primitive Kubernetes manifests at the end of the day.
A migration from one to the other is nothing more than changing some annotations or potentially transforming the "shape" of some lists or maps.