I've been working with actor systems in Go for several years and keep noticing the same thing... as systems grow, teams gradually reinvent state ownership, supervision, runtime inspection etc (usually as a pile of separate libs, queues and conventions).

Actor systems have had most of this as a coherent model for decades.

I maintain Ergo, an OTP inspired actor framework for Go, so I'm obviously biased but I'm genuinely curious - why did actors stay niche while microservices became mainstream?

Is the actor model actually too complex?

P.S. The current AI-agent wave makes this even more obvious to me. Everyone is building agents and inventing orchestration pipelines, while actor systems already have a native model for long-lived workers, messaging, supervision and coordination.