I would lay money that far more security vulnerabilities are due to overcomplicated customizability features than are due to simplified UX.
Within Office, it seems more practical to do ambitious things with Access, although that has its issues too. I apparently completely corrupted a database I've been using just by pasting part of a SQL statement that was >= 1024 characters as part of a VBA script.
Sure people could use notepad, onenote, powerpoint, other proprietary software, but they are comfortable in the grid like ridgularity of excel.
That was an uncomfortable day. ;)
Once you cross a time zone, your records are much harder to access.
There were many potential patient safety issues due to mishandling of times during that hour and the suggestion to just use the backup worked because it happens at 1 AM when little is going on other than emergencies which simply have to to manage with read-only access during that time.
I kinda like the idea of regular scheduled downtimes of stable systems, just for real experience on downtime procedures.
The business world is complex.
Some complex business software is fantastic. For example Excel. It's complex but you can do amazing things with data without learning to program (which is most people). You can use it while being on or off the Internet (this is great on a plane).
For UX many have given up security features. Many of us now have free credit monitoring because that lack of security has lead to leaks everywhere. I know people who have had their identity stolen and even attacks on retirement funds all due to companies lacking in security. Our drive for the new shiny has left many vulnerable.