I think it will happen.
Tesla is incredibly weird about adding software features. Look at things like the waypoints for navigation.. or finally using the side cameras for blind-spot monitoring. These were both incredibly easy software additions that should have been on every Tesla.. like 5 years ago.. instead, they were both added in just what? The past what 3 months?
But we do have farts.. and they keep adding video games!
As someone else pointed out, most Model Y's aren't hitting the track. So track mode is definitely isn't a high priority, on their software release train. That said, if you are selling a "Performance" vehicle.. then it's no excuse for that vehicle not to have specific modes that allow for maximum performance. If I had to guess, I would say it gets added in the next year or two.
The 4680 MYP should be significantly quicker thanks to the 300-400lb weight loss from switching to the new structured battery. I'm guessing 0-60 in the 3.1 seconds.. 3 seconds or less if they get rid of the heavy 21" Ultraturbines. Handling & braking should also increase significantly. Seems like the perfect time to add a specific track mode.. that's sorely missing.