It's not the money so much as the signalling effect to potential investors. You presumably have the best knowledge about your own ability to profitably employ capital. If you take out a lot of money to pay yourself, that implies that you believe that the business's current cash is worth more to you as personal income than it is in business equity. What does that say to people who hold only equity and are supplying the cash?

If I had investors and free business cash flow, I'd pay myself only enough to break-even on personal expenses. The reason is that I'd also own equity in the business, and any money invested in the business could presumably earn a bigger return than if I took that money out of the business and invested it elsewhere. If that assumption doesn't hold, I have no business being an entrepreneur, because it is more economically rational for me to take a fat-paying job at Google or in finance, and then stick my excess savings into index funds.