Serverless FinOps: Why Lambda Cost Models Break Every Assumption You Learned from VMs

Most engineering teams learn cloud cost management on VMs. You pay for uptime. You right-size vCPUs and RAM. You shut down idle instances at night. That mental model is correct for EC2 and Azure VMs. It is completely wrong for Lambda. When a team moves to serverless and applies VM intuition, they consistently over-provision memory, add Provisioned Concurrency "just in case," and miss the actual optimization levers. We have seen this pattern across teams that migrated to Lambda without updating h