Blanc forgot to mention that Kautsky took a position in this capitalist government, helping to mislead working people to support it. As Ben Lewis explained:

“…Kautsky’s renegacy from Marxism became evident once again in his tacit approval of the SPD’s approach. Bafflingly, he claimed that the working class had come to power in November 1918. This was deliberate opportunist obfuscation… If the Kautsky who had written of the significance of republican democracy in Marxism in 1905 had been the same person writing in 1919, as opposed to the ‘renegade’ Kautsky who had disavowed what he once wrote, then he would have been in no doubt that the working class had not conquered power.”

German revolution: diverted and betrayed by leaders of official social democracy
by Ben Lewis, Weekly Worker, January 11, 2018
https://weeklyworker.co.uk/worker/1225/german-revolution-diverted-and-betrayed-by-leaders/#3

These introductory paragraphs from Eric Blanc’s forthcoming book do not strike me as a “bold new dimension of socialist history.”  They are just an elaboration of his earlier arguments for a reformist Kautskyian strategic political perspective.  Blanc evaluates the Bolshevik leadership with sharing the same pragmatic empiricist political approach that he has.