Most of these companies like Target, Uber, and Yahoo, have never taken security very seriously, because security is a very high cost of doing business. I worked for 38 years for a top five corporation, and the money we spent on security would blow your mind. At the time I retired, there were 6.5 million attempted outside hacks each month; none successful. We hired people who spend all their at work time trying to break into our systems. They even drive around our facilities trying to hack into wireless routers. You also have to have people who get paid to do "what if" and "how could I" all day.
The most successful security requires both outward and inward facing web sites, and it requires that all data even of the most trite nature, be encoded to outside eyes. Most folks think that the "HTTPS" prefix is enough to be safe, which is furthest from the truth.
People don't really understand data encryption, anyway. They have no concepts about the nature of encryption, how the codes are actually created, and just how systems of odd random numbers help in the process. It is mind bending, but a lot of companies ignore the need.
It literally takes someone with a thief's mindset to help systems become secure. The CEO's of these companies just don't understand. They're too focused on marketing and sales.
Even Microsoft wasn't very smart when it came to handling files in their older O/S. At one time, print files moved un-encrypted from file server, to print server, to printer. No one ever thought an interruption in the process would be a problem. We had a need for instant check printing, and the files moved along, un-encrypted. One day, we asked "what if", and intentionally shut down a server before it could send the file, literally pulling the plug. It sat on the server, we restarted it stand alone without linkage to the LAN, got into the files and modified a $.01 test check to $1 million. Needless to say that this caused changes in the entire process, and that Microsoft modified their O/S to create encrypted files from applications.