I've seen A LOT of public sector projects starting out with loads of Azure services and >$3000 montly bills for applications that could've easily run on a single VM.

This a structural problem not an awareness one. Is not like they don’t know they can run it on a 5$ VPS, the problem is that there are no incentives to do so. You’d be surprised to know how much of engineering is there to address organisational challenges rather than technical ones (ie: micro-services)