I just lost an hour's work due to a power failure. I usually save more often, but didn't today. When the power came back and Illustrator launched, I was not prompted to recover a file. I checked the preferences and it said it was saving recovery data every two minutes.
The recovery location was empty.
I went on chat with support and they said, "Illustrator will, on very rare occasions, recover a file after a crash. it's exceptionally rare though. It has something to do with how and why the crash occured and only in special instances is recover possible. If Illustrator does not recover the file when you re launch the app, there's no other way to recover anything."
So there is a window that leads you to think you have a level of safety, but in practice, it works "very rarely." WTF? The interface is, therefore, extremely misleading. It probably won't help at all. If anything, this leads users to be less careful, and more data loss will result.
Can you please share the case id so that I can understand the conversation you had with the support staff.
We do turn off data recovery for complex documents as it affects performance. However there is a way to turn that optimisation off in preference File handling and Clipboard > Turn off Data Recovery for complex documents