GS-15 for tech jobs tops out at $145k all-in, and you need to have a PhD in some levels to get there. This is analogous to a principal engineer in scope. Meanwhile, they can turn around at clear $500k if they know their stuff at a place that doesn't require clearances and has good free food and stuff.
Yes, the GS table maxes out at ~150k, but they are also allowed to do locality (in DC that was ~34k), and some agencies are allowed to have a recurring bonus to more closely match external pay.
0. https://www.glassdoor.com/Salaries/principal-developer-salar...
Are there people who exist in this world who make $500k total comp? Yes, I never said there weren't.
Is that the norm, the average, or in any way common? No, of course not. The average, as listed at the top of that page, is $133,806 base pay, and $51,995 additional pay, for a total comp average of $185,801.
Some big tech companies pay higher than average, especially for exceptional people, so yes, you can scroll down and imagine unmentioned stock grants and come up with whatever number you want to, but focusing entirely on the high end of the exceptions as if that were common seems disingenuous.