This is the fundamental problem. 0% interest rates make it easier to start a business, but your startup doesn't get to borrow at 0% because there is the very real risk that your startup will fail. You'll get a nice 8% interest loan at best and no loan at all in most cases.

That risk doesn't exist for large companies but they don't have to invest their dollars domestically or even productively. They can spend them anywhere outside the US or just dump them into acquisitions and other stock market shenanigans.