I think that it comes down to the difference between not learning at all and not learning specific overcomplicated things when they're unnecessary for your use

I think that it comes down to the difference between not learning at all and not learning specific overcomplicated things when they're unnecessary for your use case. If you look at OP's examples, I don't think that any company would disqualify an otherwise competent developer for having only worked on monoliths instead of microservices or for using an easy deploy set up instead of a something with Docker and a CI/CD system. And of course OP still has tonnes of experience with their specific stack which is still quite popular - that's the opposite of being unhireable. The other part is that you might be overestimating how difficult it is to pick up something new when it's necessary. Most of these aren't that big of a deal to learn for someone with experience.