If only it were that simple buddy.
Most hacks are only accomplished through social engineering. People are convinced somehow to give up the secrets necessary. Sometimes by subterfuge sometimes by force. This is a problem which predates computers by thousands of years.
Say a big company like Experian is doing well. As a matter of fact, their business is sewed up so tight it's better than any mafia racket and just as profitable plus it enjoys the protection of the United States legal and Financial system.
Great Success, of course, makes them a Target for criminals.
To Horn in on that success you basically need to endanger and blackmail or extort. And let's face it, it's easy to do; because very few people are 100% honest 100% moral and 100% ethical in their dealings. They are also, by and large, not very brave.
Wealthy people and successful people seem to be no better at this than their poor cousins. Practically everyone is at risk.
So who will guard the guards? Well today it's electronic guards. But even those guards have guards.
One famous hack was accomplished merely by a guy who called up a company and said something like, " Hi Dora, this is Dick. I forgot my new password and I'm locked out. I need to log in under your account so Mary can get the paychecks finished on Friday.
Well it sounded like Dick but it wasn't, and poor Dora gave away access of the company's entire Financial assets to some miscreant.