Why Roberta, as many others italian musicians doens't has success in Italy but in America , or in Europe are Music Stars? There are many reasons, but a cultural and historical reason is the same for the big part of that musicians.
Jazz music never had a big success in Italy, and there is an easy reason: for 20 years - from 1922 to 1943 - under fascist regime, all music from other countries considerated as illegal.
The autarky was one of first italian fascist values - for may economic reasons, as the lack in Italy of raw materials and energy sources (oil ); one of the dreams of Italian Fascist regime was to make of Italy a big and important Country, economical indipendent from United Kingdom or others big countries of the time, and to become Italy a 'power', as the Roman Empire - that becomes the landmark of the Fascist Regime...
For that reason Mussolini made un-useful wars - before the WW-II - as vs/ Albania or vs/ Somalia and Eritrea: to build an Italian Kingdom, but the history tell us what happened.
The Italian traditional music was for more than 20 years the only music transmetted by radio and that is very important to understand what italian pubblic loves; after 60 years the 'autarky' is a way of life still follows by many people, and on Dna of many italian citizens.
Roberta Gambarini, to work as singer and to have succes, went in Usa to sing in jazz bars, but I hope a great voice as Roberta, a day, return in Italy as music star.
Roberta Gambarini is very appreciated by jazz musicians, and a big american journal compares the voice of Roberta than great jazz singers as Frizgerald and others big ones...