I agree with much what you wrote, but why is this cause for happiness? It's basically the end of programming as a profession should every company go that way.
I'm cautiously optimistic about their sudden benevolence towards open source in general.
If every company starts doing this (using open source!), the majority of software will be written and maintained by volunteers begging for donations from said companies.
What will be left is devops jobs, "full stack" engineers, i.e. all jobs where you can't really focus on developing software.
Very few interesting jobs may remain in Microsoft Research.
This is already the case for many projects, isn't it? In the case of OpenBSD, several of the core developers are either owners or employees of companies that use OpenBSD in their operations. Some of these companies are infrastructure providers, some are device / appliance vendors, some are consultancy shops...
that is not how it works now so why would that change?