“Initially when I read about Firecracker being released, I thought it was just a tool for cloud providers to use – I knew that AWS Fargate and https://fly.io used it, but I didn’t think that it was something that I could directly use myself.”
Amazon built Firecracker for its own cloud, then open sourced it. It boots a real VM in under a second. The docs are good enough that a week of tinkering gets you there without being a cloud provider. Containers won partly because VMs were slow. That excuse is gone.