Maybe not such humerous marketing.
MSE is realively new. Defender was built into Vista and subsequent OS's (7 - Windows 8). MSE needed to be downloaded and installed and was therefore still an option. Microsoft, perhaps, found a cheap way to "test the ice" , with their next OS already in mind, for free. Feedback has been excellent, so now they are ready to incorporate it.
Same with MVPs and their new award status, you could say. The award incudes their latest software. The "chosen" are known to be dedicated helpers and posters. Masses of feedback totally free!
Only humerous part to me is why their was such a monopoly explosion over their built in browser, yet total disregard for some of their other built in features.