Get in, steal a couple hundred grand, get out, do the exact same thing a few months later. Repeat a few times and you can live worry free until retirement if you know to evade the cops.

Even if you steal other stuff, you're going to need to turn it all into cryptocurrency anyway, and how much is an AWS key really going to bring in.

There are criminals that focus on extracting passwords and password manager databases as well, though they often also end up going after cryptocurrency websites.

There are probably criminals out there biding their time, waiting for the perfect moment to strike, silently infiltrating companies through carefully picked dependencies, but those don't get caught as easily as the ones draining cryptocurrency wallets.