Spin your wheels on a rough surface and it will rip grooves into your tyres, because I have done it and seen the evidence, especcially if your a heavy rider like me.
You contradict the physics of the situation. With more weight, there is more traction, which makes it less likely that the wheels will spin if you are a heavy rider and the weight is over the rear wheel. Most of us have slipped a wheel when there is poor traction and spinning a wheel where there is good traction is another story altogether. Humans can't do it. Traction is implied by gouging grooves in the tyre. There is no other way - either there is traction or there is not and the tyre will either slip without damage or move forward. You have to present evidence of said grooves and give a reasonable explanation of how this happened. Notice that I avoided the word spin and used slip. Spin would imply some revolutions of the wheel whereas a slip or a skid would be the quarter or so revolution that would be typical of your power stroke, which is only about half a crank revolution at most. Spinning past dead centre to and bottom is not doable in these situations.
And your theory of not being able to balance if you have no forward momentum and being able to "spin" for only half a crank before running out of momentum and balance holds no water either, you have no forward momentum on rollers, but you are still spinning, can still turn the cranks and still able to balance.
You cannot compare balancing on a roller with balancing on the road when you have no forward momentum. Humans on bicycles balance by way of two distinctive modes.
1) When riding forward with speed of walking pace or faster, we balance by steering into the fall. In other words, as you start to fall over to the left, you steer left and the centre of gravity is exactly below you again. You do this continuously when you ride. It is a one-dimensional version of balancing broomstick on your hand. Evidence of this can be seen when wet tyre marks show the characteristic criss-cross pattern of the front and back wheel. You cannot ride perfectly straight but have to fall left and right all the time and steer into it. On the rollers you balance in this mode. You continually steer into the fall to counter it. If the rollers were very narrow it would be impossible to ride them.
2) When doing a trackstand.
In this mode we balance like a tightrope artist by moving our bodies backwards and forwards over the centre of gravity in order to counter a fall. In this mode you cannot counter a strong fall because you cannot move left or right far enough as your wheels are planted in position.
There is a distinct transition from mode 1 to mode two when balancing on a bike since there is no position or at least a very small margin, where balance is a blend of the two. This is evident when going up a steep hill and riding in a rut. If the rut does not allow you to move left or right, you fall.
I once stopped dead on a steep hill and was spinning frantically hoping to get momentum again, when I looked down at my back wheel as I thought my chain had come off, I was in a small pothole full of chippings etc with nothing to get any grip. I had to unclip eventually though to get onto a firmer surface.
Your description of this is not accurate. Spinning frantically implies your cranks were revolving whilst you and your bike were stationery. This is not real. It is completely unlike the roller scenario because with the wheels not rolling forward, you cannot steer into the fall and thus cannot stay upright. Suggesting that you did a trackstand whilst spinning the crank brings up an equally unrealistic scenario.
