Ljós
Well-known
A very pragmatic shot at answering the question would be the sales numbers of Leica lenses. Maybe some of our specialists can chime in with solid facts - what I THINK is somewhat correct is that the 35mm Summicron is the most sold Leica lens. Please correct me if I got this wrong. So - that would be photographers voting (and zooming ;-) ) with their feet 
sparrow6224
Well-known
This discussion has ranged into some pretty esoteric -- and quite interesting -- neighborhoods considering the OP's question. For the period of its existence when it was a dominating force in 35mm photography, say from the break up of Zeiss in 1945 to the early 1960s when the SLR began really taking over, the "standard" Leica lens was a 50mm, no doubt. 35 was considered "wide". And teh 50 Summicron is still a "Kit Lens" today: you can get a "starter set" from B&H that combines the M7 and Summicron at a substantial (~$1500) discount. http://www.bhphotovideo.com/c/product/332583-USA/Leica_10546_M7_TTL_72_with.html
I would say this pretty conclusively demonstrates that Leica and its retailers often still see the 50mm as the standard Leica lens.
I would say this pretty conclusively demonstrates that Leica and its retailers often still see the 50mm as the standard Leica lens.