From the GP's post - I was trying to say I read this as "the collection of services AWS provides would require several in-house engineering teams to compete with" not "vendor lock-in".
A single service is relatively easy to replicate if it is core to your business, but an entire on-demand datacenter w/ abstractions like Time Series databases, pub/sub services, etc. isn't as trivial to do yourself. Many of these services require teams of engineers to manage at scale, and engineers that _understand_ them well.
The on-demand service catalog of the cloud provides significant value. It's more than "pub/sub" or "blob storage" as a service. It's an entire engineering organization and data center as a service w/ pre-built architectures for you to start using today.
It's not that migrating out isn't possible, it's that Amazon is providing "Engineering/SiteOps Departments as a Service" at a price that's hard to compete with in house.