(The F system did follow the pattern of most contemporaries to design stuff so that it would do what is needed now, with little regard for future developments. That's why Nikon introduced Ai (and then very shortly after that, Ai-s) mount variations, or why Canon had like five variations of the FD mount; almost all companies operated like that, with very few exceptions such as Konica AR)
Which one did the professionals end up using? Go on and search the web for some photos of war photographers in Vietnam and see what is hanging around their necks. Spoiler, usually one or two Leica Ms and a Nikon F for the times when you need to keep your distance.
There was a war on in the teens.
The Nikon SLRs picked up a reputation after being used by professional photographers to cover the Vietnam war years after the release of the first Nikon F. Were they professional cameras before professionals started using them?
I have failed to mention the Asahi-Pentax, released in 1957, which had everything the Nikon had two years later. Why is the Nikon F the first professional 35mm camera? What made it special enough to obscure years of camera development?