You don't. The way that the monetary system works in all developed economies today is that you can borrow money into existence in order to purchase an asset.

You don't. The way that the monetary system works in all developed economies today is that you can borrow money into existence in order to purchase an asset. The supply is not infinite, but it is always possible to create more. That's reality, not a hypothetical. The hypothetical is that this could continue without limit, regardless of asset prices. Thus far, in reality, that growth has always been restricted at some point. There is no conceptual requirement that it be so.