Are you actually asking this question?
Or you pretending to ask a question because you think the fact that AWS Lambda run on AWS is some huge gotcha that I never imagined and no one would ever tolerate?
I explicitly note vendor-specific baggage. AWS revenue is over 45 billion annually and half of customers use lambda.
And if deploying a lambda function on my own hardware is vastly more complex, then the tools haven't really changed, they just got outsourced.
There are a bunch of semi-standards like Serverless Framework and Knative, but nothing concrete.
I also agree there are big chunks of LAMP under the covers of running an AWS Lambda. So, in that sense, we haven't "moved on" from the old LAMP stack.
I also agree the tools are "not ours" if they aren't open. They do useful things. It's a tradeoff.
Well... Yeah?
I came into web development in 97. Back then almost everything was on shared servers, so pretty much the same thing.
Of course then you need a cluster which may be back at AWS as EKS (or not) but at least it’s more open from that perspective.