This was very much the traditional historiographical view, but it has been challenged in recent years as imposing a backwards reading of history.
Are you referring to the Sonderweg thesis? True that that's been challenged - broadly speaking discredited actually, though still regarded as important and foundational to the historiography despite that - but historians who take a bullish view of the Republic's theoretical prospects at its foundation are still rather rare. And rightly so: what happened, happened; there is no ought in history, only did.
My understanding is that Peukert’s
The Crisis Years of Classical Modernity has been enormously influential upon the current generation of historians and forced a re-evaluation of how successful Weimar actually was, especially during 1924-29, the “Golden Years”, as well as discrediting the thesis of “a republic without republicans”. But yes, there are probably still many who are far more negative about the Republic’s chances.
As for your point about hypotheticals in history, viewing everything as a series of inevitabilities is a very reductionist view, and asking about whether the Republic was doomed is not so much an exercise in alternate history as an attempt to understand its history as those who were there saw it; after all, it is they who make all history. To quote from Anthony McElligot’s volume on Weimar, published in 2009:
The idea of a doomed republic is difficult to shake off, even among a new generation of younger scholars. There is hardly a title without some reference to the impending disaster awaiting the republic and which places the republican experience firmly in the antechamber of the Third Reich. This approach to the republic continues to permeate secondary school curricula and still invades university lecture halls. And yet the picture is problematic, not least for the obvious reason that as historians we are trained not to read history backwards and yet we seem prepared to lapse when it comes to the Weimar Republic. For what these histories have in common is that they look back from the vantage point of ‘1933’. But to approach the history of Weimar Germany from this perspective in order to ask: ‘How was Hitler possible?’ and: ‘Was the Nazi “seizure of power” avoidable?’ skews our historical vision, as the German historian Eberhard Kolb has noted, and it militates against a nuanced understanding of the complex interplay of forces that shaped and reshaped the republic from its beginning. The fact is, in 1918 the republic’s future was open and its history yet to be determined; Hitler was neither its predestined nor its obvious conclusion. Weimar’s history, therefore, should not be told through this lens alone.
