Rtings did a test years ago. Granted that was with static TV content. It took thousands of hours displaying the same content to even start noticing any burn-in. And that was years ago with older panels. Recently someone did a test on Nintendo Swith OLED version where again it took thousands of hours of displaying static content to start noticing burn-in.
I did phone repairs for a few years, and would often see phones with burned in OLED screens (heck, even LCD at times)
We also see photos and video proof of people with burn in online regularly too
1. Temporary image retention can be mistaken for burn in, but it's still unacceptable to a user
2. the settings on the screen and even the ambient weather matter. Testing it in a 20C dry environment will give very different results to the people in hotter countries (my back brick walls were at 65C this summer)
1,000 hours is only 42 days of always-on use. Lets say 8 hours a day and you're looking at 120 days or 4 months before you could be experiencing permanent burn in, by your example