Not to mention, non-owner workers still bear some risk by virtue of the fact that they can be terminated at any time without cause. This in itself is a financial risk, as being without employment or income for an extended period of time can be financially devastating.
If we want to play the "risk grants ownership" game, then we have to be honest: at some point, the risk of the initial investment is paid off, and the risk the employees take on collectively matches or exceeds the risk of the investors. If we're being logically consistent, ownership would transfer as these risk pools shift. But we're not consistent, and our system doesn't value risk, it values capital.
Workers take risk not only of the financial kind (choosing to take a job at company A instead of B is a bet), as well as physical risk most times.
If we believe shareholder of a oil company is taking more risk than the worker in a platform, we value capital more than labour.