It's not just kubernetes and openFaaS, what about that thing that's a virtual appliance and requires a VM, now you need KVM. Network and firewalls? Storage as in fully replicated cannot ever lose a byte or have it unavailable storage? Object as well as block. Databases, point in time restores/backups/automated maintenance for postgres and then you've probably got a mssql server for that one app, and mysql for that other app.
It becomes just a fairly massive task back in the real world.
I'm not too familiar with the whole range of AWS offerings, but I really think aside for DBaaS and FaaS OpenStack can cover pretty much everything someone would need, especially combined with Ceph for storage.
All opensource.
It actually takes work to setup and run we are not just installing some packages and then pretending you can scrap aws.
S3 has 99.999999999% durability as standard.
I see your point that it's not technically 100% but, as close as can be reasonably achieved.
I’m not sure what this looks like outside of the US, but colocation providers offer racks of machines, or to host your machines, while providing access to cheap bandwidth and peering capabilities. It’s absolutely possible to move away from the major cloud providers. However, it will require a degree of investment within your organization to support these deployments no matter which you choose, which could be a new investment compared to using AWS, GCP or Azure.