This has always seemed the most unsatisfying assumption in the problem to me, with application to no real-life case that I can think of. The Wikipedia article has some stuff on relaxing this assumption, in its section titled “Cardinal payoff variant” (it seems that the optimal at least under one set of assumptions is √n rather than n/e, though those assumptions also seem unrealistic): https://en.wikipedia.org/w/index.php?title=Secretary_problem...
IE has been dead and buried for ages. Edge doesn't have even close to the same market share and is based on Chromium.
They build more and more of their own UIs on Electron.
I honestly don't remember when they tried to snare someone to use proprietary extensions to something open. I probably have missed a few instances.
Long story short: MS isn't a saint. They are a business. And they have behaved relatively nice for so long that some young adults don't know any other side of MS now.