Founders are not "workers" for YC. They're trying to do something exceptional with extremely scarce resources.

Founders are workers. They are the ones doing all the work and throwing years of their life away.

They are only workers if they do not to reap the benefits of their work 100%.

Indeed, they are not workers.

Workers get paid for their work. Founders don't get a paycheck.

Actually, they do. All employees of a company have to pay themselves a minimum wage, at least. Founders are employees in their own company. And they (usually) own majority stock in the company - if there is a payout for YC, founders make more money than YC does.