The founders aren’t really taking on that much more risk than the rest of the early team; it’s the VC’s money, not theirs.
I absolutely don’t agree with the idea that employees deserve the same upside as founders (because I think initiative and persistence against adversity/inertia is insanely rare and valuable and should be rewarded immensely), but it is not an insane proposition.
It’s especially popular among people who think the actual work output is more important than the leadership initiative. Both are obviously essential, and founders do both, while employees do only the first (or they’d be founders themselves).