If you look at engineering salaries in Germany, 90-100k is what you pay for a senior engineer or PM, not a mid-level one.

Salary is not the same as paying a contractor. So, while salaries for senior engineers is 100k, as a contractor they might be charging 150K per year ($75/hr).

Yes, true.

Is this the thing where the 99th percentile people somehow think they're the average? I see that a lot on Reddit for some reason.

It is a selection bias, plus perception that the people with more (the 0.01%) are a lot more common. "I dream of being rich, and to me rich is..."

More specifically:

To be in the top 10% of earners in the USA, you need an annual income of at least $148,812

To be in the top 5% of earners in the USA, you need an annual income of at least $352,773

The median salary in the USA is approximately $59,428 per year