Minikube doesn't solve the same problems at all. It solves one small part of what Sidecar does. Also note that Sidecar has already been around for 1.5 years and

Minikube doesn't solve the same problems at all. It solves one small part of what Sidecar does. Also note that Sidecar has already been around for 1.5 years and so when you say "rolling your own" it implies that this was a decision to not use something already available. But there wasn't anything at the time. And there really still isn't anything else that works across any deployment/scheduling platform in the same way.