> once you can get a startup off its feet, the VC money from seeds easily makes up for that downtime

The depends a lot on the startup. Many startups don't take VC money.

Of those that do, in my experience as first non-founder employee, the founders were paid very little compared with employees, on the hope of future success with their equity instead, even after the startup got decent pre-seed and seed investment. Both rounds of investment were enough to pay some key employees well, but not to pay everyone well for long enough. So the founders felt they has to continue with low pay for themselves.