That's an interesting point. Unlike dollars, made money doesn't sit in a bank, to be loaned to lenders creating a profit for the bank, part of which gets paid as interest. This drives economic expansion.
I don't even know how you would do something like that with bitcoin.
It could though, if places like Coinbase decided to transition into a banking role. The issue with Bitcoin in my mind is that people now view it as more of an investment than a currency.
But a loan is an enforceable contact. You would have to marry the loan somehow with something that would give it teeth. This is an interesting problem.
Banks work in a legal and regulatory environment which bitcoin lacks. That's the problem, there are a lot of details that would have to be worked out to make that happen.
I don't even know how you would do something like that with bitcoin.