I suspect the success of a camera line depends on who is selling it. In the US, during the '50s Asahi/Pentax was sold through Burke & James - a large camera wholesaler in Chicago (perhaps better remembered now for the low-cost large format cameras they made and sold. Around 1960, Heiland Photographic (Honeywell) started selling them in the US (and I believe Canada).
in the '57-'62 timeframe we sold Exatka, Alpa, Pentax, Nikon, Canon and Bessler Topcon SLRs.
In my 5 years at the store, I don't remember anyone from "The importer for the Edixa SLRs was also the importer for Praktica and Exakta and supposedly wanted to promote the cheap Prakticas and big buck Exaktas more than the Edixas which slotted in the middle" stopping by our store (which was in SE Michigan). The situation in NYC might have been different. As noted we did sell Exxaktas but I don't remember the wholesaler we used.