What is your definition of developer-first? My experience working at Microsoft in 2015 was the opposite of what you describe. They were too focused on supporting legacy MS that they couldn't innovate or find and keep talented developers in open source because they were forced to adopt tools and frameworks that were crap compared to standard open source development tools.

The only reason people went there usually was for the money and once they got enough to follow their passion, they left because none of them were passionate about Microsoft.