Your mileage can certainly vary with work-life-balance in FAANGs - I've been at Alphabet for almost 7 years and I've had great WLB. It's something you have to do deliberately, though; especially with distributed teams, there's always going to be emails coming in, chats to read, documents and CLs to review, etc. If you're someone who tends towards workaholism you may need to set some boundaries in your life.

I'm not saying this is universally true at Alphabet, as there are definitely groups that don't do a good job of this, but it's very doable.

That may still work when someone is in his 20s. For someone in mid-30s/early 40s, it's too much of a gamble, especially if one has a family to support.

One starting from zero doesn't gain deep expertise in anything in a startup in the span of a few years. As long as the market is breaking one record after another and money is raining from the skies, this is not a problem. But it's an illusion and like all illusions, eventually will collapse. And when it does, you're at the bottom of the totem pole and as expendable as one can be. And this doesn't even take into account technological progress that is rapidly obsoleting many of these low-barrier-to-entry jobs.