Most popular history I’ve read tends to attribute the success of the Protestant Reformation to the movable type printing press. I haven’t actually read much history explicitly challenging the idea that that the printing press was key to the success of the Protestant Reformation, but it seems suspicious to me.
I had some stuff written about why I regarded the link with suspicion, but I realized it was veering away from actually asking a question and more toward soapboxing (Although I still might post (parts of?) it if anyone asks why I find it dubious), so I'll just ask: do most historians attribute the success of the Protestant Reformation to the printing press to the same degree as more general audience histories?
While the invention and development of moveable type was certainly one important (very important, even) factor in the spread of the Protestant Reformation, it was still just that: one factor. Many factors were crucial to the movement's success: woodblock prints like Cranach's, for example, along with festivals, sermons, hymns, and simple word-of-mouth exchanges.
However powerful the printing press may have been, the pulpit--a distinctly oral tradition--was probably among the most influential means of spreading information. Sermons, by the time of the Reformation, were moving out of the churches and occasionally into more public spaces (out of necessity, at times). They were also becoming more active, participatory exchanges, in which congregations played an important role and were not just passive recipients of information (which was how Catholic sermons were characterized).
Much printed material was also likely to have been read aloud, either to oneself (a not uncommon mode of engaging with a text) or to others. Printed materials were also intended to be shared and discussed and debated. In cases like this the lines between "written" and "oral" culture become increasingly blurred (they're always blurry, but today we tend to forget that).
Also consider that whatever innovations the printing press brought--and they were many--the printed word was still limited in how fast it could travel. Information moved at human or animal speed, just as it had in the days when all (or nearly all) texts were copied by hand.
While I hesitate to characterize what most historians think, I would venture a guess that many historians of early modern Europe would suggest that lots of really complicated factors are important for all sorts of historical events, movements, etc., and that no invention--even one as important as moveable type--exerts its influence in a vacuum.
For more on the importance of oral culture in the Protestant Reformation, see especially Robert W. Scribner's works: his book For the Sake of Simple Folk: Popular Propaganda and the German Reformation (Cambridge U Press, 1981); and the article "Oral Culture and the Diffusion of Reformation Ideas," History of European Ideas 5 (1984): 237-256.
Whilst there is certainly more to say, you may be interested in a recent answer by u/Stormtemplar, which addresses some related points.
