I think k8s starts making sense when you have to manage more than 10-15 machines. Better yet, 50-100 machines. Especially if these 200 machines actually run 3-4 types of containers total.

Usually it's rather unlike a sane dev setup. Even if your prod setup uses hundreds microservices (you're Google or Uber or something like that), you don't want to run all of them in your personal dev environment, you reuse 90%-99% of stable microservices running in the QA / integration / whatnot environment, and only run a handful locally.