All data breaches happen because the data is protected with a single (or several) protection level.

For example, suppose that there are 100,000 files, which are placed into a cloud warehouse and then this cloud warehouse is protected with a single password. Hackers, now, have the following problem:

Problem A How to hack the single password to the cloud warehouse?

If in addition to this single password, we protect each file with a unique password then the hackers have the following problem:

Problem B How to hack the 100,001 different and unique passwords?

Problem B is 100,001 times more complex than problem A. This complexity, also, creates complexity in management of 100,001 different and unique passwords (passwords fatigue problem). To solve the last problem DPGs are used. See example, here: https://www.publish0x.com/simple-solutions-to-complex-problems/a-simple-way-to-protect-multiple-content-files-xxvzoww

For the reason that problem A is significantly less complex than problem B, but most of businesses/organizations base data protection on the problem A, data breaches are happening.