If it isn't sealed then why doesn't oil leak out?
I know it isn't as well sealed as a bottle, but it is designed so outside fluids can't get in and oil can't get out. How much condensation can there be if it is sitting in a garage that is -20F to +40F all winter?
It's not the condensation that's the problem, it's the oxidation. The water will all boil out on your next long drive. But that oil is exposed to oxygen in the crankcase and degrades over time.
What RobbieB said, plus, if you have driven it at all, you've had combustion blow-by get into the oil. So it sure is not the same as a sealed bottle on the shelf.
I'm impressed that it includes time, I'm not sure about my 2017 GM, but our 2011 Honda manual said to change oil once a year, regardless of the oil minder (which often still showed a good % left, as we drive low miles).
I'll add that for all those years, we were told how bad short drives are on a car, and how we need to change the oil more frequently. But most of our trips are short, like 5 miles, only about 3 for DW to work. I know the oil minders factor that in, but we still usually have % remaining after one year.
Sunset:
I don't have one of these fancy, oil GMC diagnostic reports (is this in the vehicle, or you take it to the dealer for an oil report ? ).
The oil minders use an algorithm, the subtract points for each start, run time, speed, load, monitor the temperature and a bunch of other things, with different point values for each ( a very cold start counts more than a hot start).
-ERD50