I believe that microservices (but under a different model than K8s et al expose) are posed to make a huge comeback soon due to agentic development. My company has been investing significantly in this direction for a while, because agents need better APIs/abstractions for execution and interaction with cloud environments.

Once Claude Code came out something new clicked with me regarding how agent coordination will actually end up working in practice. Unless you want to spend a time of time trying to prompt them into understanding separation of concerns (Claude Code specifically seems to often ignore these instructions/have conflicting default instructions), if you want to scale out agent-driven development you need to enforce separation of concerns at the repo-level.

It's basically the same problem as it was 5-10 years ago, if you have a bunch of logic that interacts with each other across "team"/knowledge/responsibility/feature boundaries, interacting with your dependencies over an API, developing in separate repos, and building + rolling out the logic separately helps enforce separation of concerns and integration around well-specified interfaces.

In an ideal world, Claude Code would not just turn every repo into a ball of mud, at least if you asked it nicely and gave it clear guidelines to follow to prevent that. That was always true with monoliths and trying to coordinate/train less experienced developers to not do the same thing when, and it turns out we didn't live in an ideal world back then so we used microservices to prevent that more structurally! History sure does rhyme.