"You can [accurately and meaningfully measure software engineering productivity] - but not on the level of a single developer and you cannot use those measures to manage productivity of a specific dev."
At the level of a company like Google, it's easy: both inputs and outputs are measured in terms of money.
I am not Amazon person - but from my experience 2 pizza teams was what worked and I never implemented it myself just what I observed in wild.
Measuring Google in terms of money is also flawed, there is loads of BS hidden there and lots of people paying big companies more just because they are big companies.
"You can [accurately and meaningfully measure software engineering productivity] - but not on the level of a single developer and you cannot use those measures to manage productivity of a specific dev."
At the level of a company like Google, it's easy: both inputs and outputs are measured in terms of money.