I guess that I was expecting AWS Lambda to scale up immediately in the same way the ALB or SQS scales up with demand. That assumption was very wrong. Edit: my

I guess that I was expecting AWS Lambda to scale up immediately in the same way the ALB or SQS scales up with demand. That assumption was very wrong. Edit: my AWS support rep explained it: Without pre-provisioned capacity, it would take 34 minutes to scale our Lambda functions to the peak concurrency we needed. And it would cost several thousand dollars. Completely insane cost. Also, EFS is ridiculously expensive.