Fully agree, doing reactive autoscaling when the actual boot time is slow is an inherently hard problem. We've done years of research into building specialized VMs (unikernels) and fast controllers to be able to provide infra that allows VMs/containers to cold start, and thus autoscale/scale to zero in milliseconds (eg, a simple Node app cold starts in ~50 ms). If interested, you can try it out at kraft.cloud, or check out info about the tech in our blogs (https://unikraft.io/blog/) or the corresponding LF OSS project (www.unikraft.org).