Yes. That's what I mean. The per user basis does sound interesting.
Sometimes though, you can't force a square peg in a round hole. I dislike server maintenance but docker is a decent alternative to lambdas if you can absorb the extra cost.
Agreed, I think that's the state of the art: if variable concurrency is important, manage your own spare capacity. But I expect AWS and other providers will some day let us pay for reserved capacity without managing it, and I can't wait.
It does. But if your endpoint is so inactive that it sits idle most of the time, having it on a server/ec2 instance means you are paying 24/7 for it to sit there not doing anything. You could argue that it's not that much different to pay to keep the lambda warm vs paying for a server to be idle half the time.
Sometimes though, you can't force a square peg in a round hole. I dislike server maintenance but docker is a decent alternative to lambdas if you can absorb the extra cost.