I think this kind of user abuse is intentional. If people put the time and energy, and emotional effort into understanding a piece of software, they're less likely to jump ship.
Wouldn’t that suggest it is accidental? Making it harder to understand a piece of software seems to cause people to look for easier to understand alternatives.
If the software has a small marketshare and is struggling to get new users, then this would be true. When the software is already hugely dominant, the same dynamic does not apply. Trying to lock-in customers when they're not customers yet is a bad idea, but when they're already your customers, it makes business sense.
I think, MS Office products provide superb usability for those who make and/or influence these decisions: those who are installing the software. The enduser isn't really in that loop.
