Financing is one of the major hurdles of employee owned businesses trying to compete against investor owned businesses, so you're right to identify that. I have 4 main solutions to this problem:

1. Investment isn't the only way to raise capital. There's also loans. In a fully co-op economy, the financial infrastructure for loans would likely be more robust. This is already how a lot of businesses get off the ground.

2. A company doesn't have to be 100% employee owned for the employees to have a controlling stake. An employee-owned company could decide to sell off 49% of its value to raise capital. They could do this at any time, including during startup.

3. The average worker would have more money to do as they please. In 2023, American companies earned a profit of $22k per worker. In a co-op economy, that's an average of $22k each worker has control over that they currently don't. Your average worker would be more capable of making the type of investment that you described.

4. Companies don't necessarily have to start as employee owned. A normal path for an entrepreneur is to start a business, grow it until it's sustainable and later sell it to somebody. Instead of selling it to an investor, they could sell it to their employees. In a co-op economy, this would probably be required in some way or another.