I agree with many of your points, but I think that in 11 years, you're basically starting to approach being a senior engineer. If you look at full stack, there are many, many technologies you need to understand, and every time you go back to each, there are things you will see and understand that you didn't last time (i.e. the knowledge you thought you had wasn't actually accurate), and then the technology is always changing, so you have to constantly add to that. And, as you get more senior, you start to realize that most of the resources out there aren't 100% accurate either, so you actually have to spend a fair amount of time figuring out what the real truth is.

And it's the knowledge of how to do this and _that you need to do this_ that makes a true senior engineer. And honestly I have never seen anyone in their 20s that knows this or knows how to do it, and few people in their 30s either. But since this is the core insight that makes one senior, yes, if you had it, you would have something to bring to SpaceX if you totally switched verticals, because you'd be able to "quickly" ramp up, skipping over much of the phase where you're confused by your own incomplete/inaccurate assumptions and by just ingesting inaccurate resources without testing them out first.