My impression was that there was a stint where about all you saw were the Ndisles type of maps with longer distances between bases and lots of CVs. It just so happens that during that time the LA-7 was updated.
The plane that benefitted at that time was the F6-F, which had a jump in usage, and the LA-7 declined pretty significantly, IMO because it's flight time was too limited to press any kind of attack with it.
Now that people moved on to other aircraft, they just haven't gone back.
That is my opinion and impression.
That having been said, it would be interesting to see some hard data to see if there indeed was a performance hit with the update, but I suspect not.