[oldE]

Having watched the races and tire changes I would also submit that the difference between a well scrubbed tire in good racing condition and a tire which "has fallen off the cliff" performance-wise is not something which lends itself to TV. In previous years you could see the tire degrade and get a feel for when it was nearing the end of its life. Now the only ones who know are the driver and those with the telemetry (or timing the laps).

The change in performance seems to be due to a chemical/physical change in the structure of the rubber. Not something one could necessarily judge at a glance.
Watching Vettel catch up to Hamilton in the last five laps and the performance of the rubber in the last corner was an excellent indicator of the rapid and dramatic changes these tires can exhibit. But I couldn't tell the difference by looking at the car.

Best
Les