Because the original definition of FAANG was for the investor crowd, and looked at companies solely from the perspective of their stock performance and "potential growth". Microsoft wasn't supposed to be good at either back when this was coined.
We now use it in very different contexts, though, such as when discussing employment practices and internal work culture of those companies. In that particular context, I think Microsoft does belong there.
I always assumed it was because they're not headquartered in Silicon Valley.
I understand if someone working variable part time[1] hours for minimum wage cannot afford to lose their job. There isn't any room for sacrifices when you already have to e.g. decide each month if you can afford to pay for both food and utilities, or if you aren't going to have hot water for a while[2]. Yet even though they face far higher risks than the average tech worker, sometimes they still choose to make sacrifices[3].
Yes, you might get fired. You might have to adjust your standard of living. Banding together into larger groups can help to mitigate some of these costs, but regardless, the average tech worker is fortunate enough to be able to make a significant sacrifice.
[ This is why some of us try to warn about growing problems early, when the cost of counteraction is low. Unfortunately, most people decide to ignore the problem because it isn't an obvious, widespread, damaging problem. ~sigh~ ]
[1] different, computer-optimized schedule each week, could be anything that still counts as part time (including 0)
[2] https://medium.com/@sarahkendzior/the-minimum-wage-worker-st...