actually, a lot of the earlier tracked vehicles like that were not designed with neutral steering, and thus couldn't turn on a dime in the way you are suggested, instead being steered by a clutch and brake system, which basically removed the power to one tread when turning, requiring them to keep moving forward as they turn. with such a system, the longer the tracks, the shallower the turns they could do without throwing a tread.
steering through a Double differential system, which maintains power to both treads the whole time and allow you to put the treads at differernt speed to turn, even put one tread in reverse to turn in place, was a cutting edge feature mostly pioneered by the Germans with designs like the Tiger and Panther, as well as some british ones like the Churchill, only after the war becoming fairly standard.
Funny you should mention the double differential method of tank-steering, since the French developed it in 1921. The Char B1 had a continuously variable output for its tracks allied to a hydrostatic transmission. During trials, the Char 2C did indeed experience track slippage in tight turns (it used a different engine for each track, by the way; interestingly they eventually became Maybachs, which Panzer fans will notice as being familiar) but it never once actually threw a track.
As far as I can tell, the Char 2C used a controlled differential, whereupon there are effectively two gears (epicyclic gearing) with an idler wheel, the second of which is clutched in or out so that power isn't wasted. This system--with the usual operator-controls being two wands--is typified by the M113 series or armored vehicles. I will submit that the Char 2C was a beast and certainly not fast (10-15 kph max) nor particularly mobile (whether that last issue was a concomitant of its great weight, the size of its tracks, or insufficient track-shoe articulation is open for debate.
And "turning on a dime" is relative. There are videos of Char 2Cs in motion, but not too many of them turning, so I am not sure we will ever know for certain. But a tracked vehicle of a given size turns more closely than an equivalently sized wheeled vehicle. And you will note that I never stated that tracked vehicles or other skid-steer vehicles could all turn from a stand-still/idle. But I bet the Char 2C could, though it might be painful to watch. For what it is worth, it is relatively rare for any tracked military vehicle to neutral steer completely in place as it puts too much strain of the individual shoes and track-pins holding them together, thereby risks throwing a track.
For example, take a look at this St. Chamond in 2017:
https://youtu.be/sFTUkmj3gaUhttps://youtu.be/1jkYUUGK09INot moving around too badly for a 100-year old fighting lady when you think about it.
Here is its replacement, a little guy that can skid steer wherever you want:
https://www.youtube.com/watch?time_continue=9&v=GdPb5PCpivE&embeds_euri=https%3A%2F%2Fwww.bing.com%2F&embeds_origin=https%3A%2F%2Fwww.bing.com&source_ve_path=MjM4NTE&feature=emb_title
