If I make $100 in a year and spend $1000 that year, my income is ($900). How can I spend $1000? Generally through loans and bonds. How do I secure said loans? Generally simply by showing how much VC and income comes in with a business plan that banks accept.
But that's the secret to the money flow. That's also partially why the collapse of SVB was such a blow to the tech industry. A LOT of loans were issued by them.