Value that can be extracted will be. As a founder, you have a large, if not the final say on compensation. Founders therefore pay themselves as much as they can while keeping the business healthy.
I think this is a greater factor in the relatively high compensation than "value added" or "risk taken".
Founders don't have the final say on compensation! The market does! If you think you're worth 5% of a company you're applying for, demand it. If you're worth it, you will get 5% --- maybe not from any specific company, but from some comparable company.
If you think you're worth 10-20% of a company, stop applying for jobs and go start your company.
It is absolutely a seller's market for talent right now. If you aren't getting what you think you're worth, you have nobody to blame but yourself. Your current company may not give it to you --- for the role you fill, they may believe you're replaceable for less cost --- but that doesn't mean you can't get it on the market somewhere. But you have to make the effort. People absolutely cannot in the real world whine that things "aren't fair" and expect improvement.
I think this is a greater factor in the relatively high compensation than "value added" or "risk taken".