Your optimism is refreshing but ultimately wrong. We did "solve" those problems but then immediately 10xd the incidental complexity of both our development and operations work in exchange for nothing.
I'm not sure where this 10x comes from but if this is about modern on-demand CI clustered runners vs old timey dedicated hardware and servers, then you have to take into account the fact that those hardware and servers were never properly cleaned of their mess, hard to configure, and had low general availability. This switch was a big gain IMO, even if docker and k8s are far from being simple to operate.