I've had 5+ friends leave Meta or quit software engineering altogether after E6. Either the responsibilities and stress were too much or what they were being asked to work on wasn't really aligned with their core interests. Business needs are always changing, so it can be a common occurrence to take a lot of ownership over a project you don't have personal interest in.
It's important to be adaptable, but I think intrinsic motivation can be hard to sustain if the people, project, or priorities are in flux.
For the older crowd, what really typifies career longevity in a software engineering?
L6+ (i.e. Staff+) at Big Tech is just really stressful, and Meta is one of the more stressful companies out there unfortunately. I know a couple Meta E6s who left to become L5, purposefully down-leveling themselves. In general, I know many engineers who purposefully stayed at L5. The amount of impact necessary to sustain L6 and above is just staggering, and it's unfortunately not completely in your control.
For the older crowd, what really typifies career longevity in a software engineering?
I don't think I qualify for "the older crowd" yet, but for me, it's a mix of:
I have seen engineers fail time and time again at these. It's ironic as if you mess up at #4 in particular (i.e. you obsess over title and money), the other points tend to break as well and you weirdly end up with pretty bad career growth.
I'm really not a career gamer (e.g. when I went to Meta, I literally didn't interview at any other companies to get competing offers). I've never super-consciously thought about level or title; I just sort of naively went to places where I thought the people there were cool and I could build cool stuff. And when I wasn't able to build enough cool stuff at work, I would build cool stuff outside of work (i.e. my side projects). Despite all this, my career progression (and my compensation progression) has been faster than most (in 2021, my income was pretty close to being in the top 1% of California earners).
I cover more of all this across these:
I've been in engineering for more than a decade and I am still working on the exact same technology that I have since the beginning of my career (Android). I arguably have a pretty bad WLB but I'm still alive for whatever reason. I disagree with Alex about this point because there is no shortage of engineers willing to work twice as hard as you to kick your ass.
I'll be very specific with the reasoning.
At any rate, let's work backwards; what qualities would you need to have 10 years ago that would allow you to be relevant today?
You will find this knowledge will compound over time if you stick with it while everyone else is jumping in and out, desperate to catch up. That historical context will help you immensely.
Technologies change but best practices rarely do.
One confounding variable here that may explain why so many people in tech quit early: they make a lot more money.
Money gives you optionality, the ability to say "F you" (probably in nicer terms...) and just quit. So if you've been an E6 Staff Engineer for a while (5-10 years) at a top tech company, there's a good chance you never need to work again. This leads to tech employees quitting or exploring other career paths (angel investing, real estate, etc).
Contrast this to other industries, where the employees have to put up with monotonous work or poor working conditions, simply because they need the paycheck.
Not sure about "fu money" is attainable as a Staff Engineer though without holding a lot of the stock and it compounding at 30% year over year (which cannot happen forever). There is only 1 engineer I know who is Staff+ who is in VC/Angel investing but that is only because he had a buyout in a previous job.
IMHO FU money starts at $10M. Not even $3M is FU.