I last raced before either slicks or block patterns were in general use. Condensation rising from tyres wasn't unknown but the tyres certainly weren't very hot. Certainly we knew that tyre pressures should be raised in the rain. I did notice that on tracks that were old EFTS i.e. airports, the very coarse flint surface of the runways gave excellent traction wet or dry. These surfaces also had a wonderful grip on leather when they met. There were many interesting, nay fascinating, moments when one transitioned from the old flint surface to a newly laid asphalt patch in the wet.
I remain unconvinced that temperature raised by hysteresis is the main cause of the superior performance of block patterns. I think that increased unit pressure has more to do with it. I am willing to learn, however. Can you direct me to any scientific or engineering paper on the subject?