That’s not the simobject limit causing that, there’s definitely something else going on.
If you configure GSX right you really have to push it to hit the object limit. I’ve only been able to do it with both GSX enabled and all of FStraffic’s ground features turned on which would be a crazy thing to do anyway. Even if you hit the limit you would only see missing aircraft / ground vehicles. It would definitely not lead to whole airports disappearing.