I'll never understand why they tried so many versions even under Bridgestone. The colored sidewall in ChampCar/IndyCar is very simple and very easy to understand and see for everyone. Instead they tried all kinds of stupid, hard to see stuff like the white groove and so on. Why?!
The American solution really is awesome. They even used the colored sidewalls to indicate the cars that are still in the contention for the championship at late stages of the season. And it worked. It's not shameful to learn from the Americans how to present something to the spectators/TV viewers. That's one thing the Americans do handle smartly.