Dear Massimo, in fact BMW in the 1980s with the System, a modular helmet presented in 1981 and sold in 177,000 units worldwide, gave an important boost to the helmet market.
Its successor, the 1989 System II (the one with the “golf ball” shell to reduce noise) had, among the options, the visor heated through metal filaments. This innovation, however, was not re-presented in subsequent models because, while effective, it resulted in a significant increase in weight and modest autonomy.
Today the problem is almost solved thanks to Pinlock, the double visor available as an accessory for almost all helmets which creates an air gap capable of reducing fogging.