This is knitpicky, because OP's point may still stand, but as a founder, this is what comes to mind after reading this: When I hear "work for a startup", I don't assume that means "be the 10th engineer at a company". You might make some money at that point, but you're not going to get financial independence unless there's a billion dollar IPO.
By BigCo standards, 10 engineers is a tiny startup. By venture/founder standards, I think 10 engineers is when you've already made it past the riskiest parts. You probably already have significant revenue traction, or you're past a Series A. You should be able to pay market, and equity is about alignment not risk compensation.
I think you can still get rich at a startup, but you need to take actual risk to be compensated for it. Join a 5 person company. Be the second or third engineer, and be able to become the CTO if the two technical people ahead of you leave.