EDIT:
Originally, I was posting again to say I had the same problem after SU12.
I stand corrected… with “AI OFFLINE” selected, after flying around KLAX for about 20 - 25 minutes I did eventually see a couple of airliners land, taxi, and take off. However, it was only three that I saw after watching for another 10 - 15 minutes… so, very sparse air traffic despite the slider being set at 100. Not what I expected. Also, the AI aircraft don’t display labels like the REAL-TIME ONLINE do. Given the sparsity and the lack of labels, I may have missed the odd one earlier today when testing.