There have been a number of changes to Amazon's policies over the years, and personal participation ("outside activity") is really straightforward now. For the vast majority of cases you just need to submit a ticket with details, and then it is auto-approved.
For comparison, you can have a look at Google's open source policy on personal projects here: https://opensource.google.com/docs/iarc/
If you are an employee and have questions, drop me a line at msw at amazon.com
So the prospects of Amazon reimplement all the popular open-source software someday is viable?
Amazon's policy on outside activity is very reasonable.
But honestly, whether the companies are 'right' or not isn't my point, and I hope it's not what people take away from my ranting. I only wanted to make a point about the narratives around FOSS being destroyed. People chose to build businesses on open source; sometimes it worked, sometimes it didn't. That's all we're learning.
Contrary to reports of its death, open source is alive and well.