I think the main cause (that's actually quite anti-capitalist) is that banks and people at power have the ability to create money out of nothing, to lend the money into existence, while devaluing everyone else.

It was very interesting to me where I finally understood how banks (and the overall system) create money. As a bank you start with 0 money, you lend 100 to some person that you "deposit" into their account at your bank. So now on your books you have 100 in liabilities (the money that the person has in your account) and 100 in assets (the money the person owes you). So accounting is balanced. You did not need money to start with, as a bank you just "lend it into existence".