You have made a choice to not work at companies that make money off of proprietary software, then you exclude the vast majority of the market of commercial software engineering, but that also means you have no idea of or don't care market rates are. So, you really shouldn't comment on that unless you figure that out, and it's a little disingenuous to do so this way.

You are paying $100,000s for that choice. Your choice does not mean everyone else is overpaid.