Be careful of generalizing. Assuming all your other parameters are such that 7k or more is reasonable, then yes, GC is very much capable of going well beyond 7k. I ran a fill of it for just over 10k miles (13 months), but that was in my wife's Sequoia, whose 4.7L V-8 is extraordinarily easy on oil. The UOA, which is posted, showed substantial oil life remaining.
On the other hand,
your situation might not be appropriate for a 7k run, even on a robust oil like GC. From what little we know of your operating conditions, I suspect you'll probably be fine. All the more so since you've already gone to 6600 miles, apparently with no problems. Your chances of having a failure in the next 600 miles would seem low. But if, for example, you often travel on a badly dusty dirt road, your engine is having FI or PCV issues, you do a lot of very short trips, etc, you may not be safe at this point.
You should try an occasional UOA to get a better feel for where you stand. As I've said here before,
knowing is so much better than guessing and speculating.