You're still missing the forest for the trees. All of this was created in the last 2-3 years and already it's replicated most of what's in traditional finance. It's the rate of innovation that is important, not the current y-intercept.

Furthermore this is a global system that anyone can contribute to. How hard do you think it is for I as an Australian to build a financial firm that interfaces with Bank of America or the NYSE? It's almost impossible. In DeFi I can spin up my own app in days.

Aave is used for being able to borrow against your crypto assets, so if you need a loan you don't have to sell, this isn't a service any bank offers. You can also just deposit your assets and earn interest on them.

In 2009 most of my colleagues similarly dismissed AWS "Oh it's just some easy storage with a way to spin up servers, big deal. Bare metal is cheaper and easier". It wasn't until most business components were automated that it became an obvious choice.

Now imagine you're starting a new financial firm and want to offer an exchange, options, perpetuals, savings accounts, loans etc. You could build all these pieces yourself for a few million dollars and a few years work. Or you could use DeFi protocols, build a nice easy to use front-end and be up and running in a few months.