system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: PayPal seems like it would be a goldmine for hackers, given all the bank and credit card info it stores. Yet, I've never seen stories about it being hacked. What does PayPal do that other businesses (e.g., Target, Home Depot) aren't doing?
gpt
Trying harder most likely. The fallout from Target losing customer data is far, far outweighed by the fallout from PayPal losing its data. PayPal would likely be forced to close their doors from that sort of thing.

So the pay for the best in security and are willing to deal with a lot of inconvenience if it means security is better. a proper security setup means that no one vulnerability would give full access to everything. A good setup, for example, would mean that you'd have to compromise multiple systems to get at the most important data and would mean you have people watching closely for just such compromises in progress. 

It's a bit like asking what the bank is doing with its vault that the hardware store isn't doing with its cash register. They're both locked, sure, but some locks are better, if more expensive and hard to maintain, and the bank is certainly watching a lot more closely.