Sorry you think it is silly/not relevant. I believe my theory applies to everything you've just described... I'll try again. You say TTO unloads weight from the rear, losing traction. I agree. But what I believe this is doing, on the microscopic level, is reducing the contact patch of the rear tyres, concentrating the traction down to a very tiny area of the rubber surface, which then goes through the temperature fluctuations I described which reduce grip. I believe the tiny part of the tyre surface that remains 'loaded' has exceeded the heat 'limit' if you want to call it that - that is what is resulting in the slide. I mean, if the rear tyre was completely unloaded, it would lift off the ground, and cause an instant spin. We're talking about the rear being partially unloaded in an oversteer situation to reduce grip, not remove grip entirely. So in that instant, part of the tyre is still 'loaded', and that part is going nuts (while the rest of the tyre is at normal temperature). I mean, how could it not be going nuts? It's the only part of tyre left touching the road after the rest has been unloaded, and it is in slip. It is being dragged across road. There is friction, so there is heat, at the microscopic level. The molecules of rubber in direct contact with the road in that instance are having a really bad day.
I think my understanding of the 'cliff' in the current F1 tyre differs from yours, because I don't think it's relevant to what I was describing (or indeed, what you just described about entering a corner on the limit and spinning). The 'cliff' is a consequence of tyre wear, which causes the overall performance of the tyre to fall away after an extended period. This is not the same as the temporary loss of grip I'm describing during a single instance of slip, caused by the rapid surface temperature fluctuation. Such fluctuations return to normal immediately after the slip, and the tyre returns to full performance. The tyre surface is constantly fluctuating in temperature as you take corners, and by 'looking after' them, allowing the surface to return to the normal operating window after each corner, you can reduce overall wear and postpone the inevitable 'cliff' which happens when there is not enough rubber left. I wasn't talking about that. To put it in the context of GT6, the colour describes surface fluctuation as the cause/effect of slip, and the bars in the centre (which presumably go down in endurance events) would show the 'cliff' if it was an F1 tyre, with the wear decreasing at a fairly constant rate and then suddenly dropping away.
Again, you have separated what I believe is part of the same process. All unbalancing of the car you describe is just shifting the loads around the contact patches. You have repeated yourself so I'd better do the same - during TBO/TTO, the rear doesn't have enough grip as you say, because the tyres are unloaded to the point where the contact patch is tiny and going through concentrated temperature fluctuations on the surface. As for power oversteer, the weight transfer is to the rear, so the tyre is heavily loaded with a bigger contact patch, and a much more violent force (from the engine) needs to overcome the traction and cause all that surface heating, which happens much more rapidly, hence the snappiness.
Rain adds extra complication, and indeed traction is reduced overall by the liquid element. But where rubber meets road, it's the same deal. There are still parts of the rubber in direct contact with the road just the same as in the dry. The water is dispersed into the grooves, allowing small sections of rubber to touch the track. These sections, under slip, will again go through surface temperature fluctuations that change the grip level. I know it seems crazy to suggest that even in the rain, the rubber can overheat. But I think does, but I stress again, on a microscopic level, not the whole tyre. Look at the wet tyres in F1 - in wet starts/restarts, drivers on full wets weave side to side and do burnouts to get them up to operating temperature just like a dry tyre. If the rubber remained cool all the time in wet conditions, how could they heat tyres in this way?
TL;DR I believe any slip, from a massive drift to the subtlest TTO, causes significant temperature fluctuations on the tyre's surface at the microscopic level, which directly affects grip levels, moment to moment. It doesn't affect overall tyre performance unless the surface is overheated for an extended period of time (or if it is an extreme burnout that ruins the whole tyre in one shot). As long as the surface can return immediately to normal temperature after a slip, the overall performance will stay roughly the same until the tyre is completely worn.
