But don't the Cyclo standard and Oppy derailleurs (which use two jockey wheels) precede the Simplex by a dozen or more years?
There are always exceptions to the rule. The Nivex parallelogram derailleur predates the GS by 13 years. But as the parallelogram derailleur was widely accepted after the GS, twin jockey wheel derailleurs were widely accepted after the TdF.