Aside from your complete lack of any actual experience in riding a fixed gear bicycle you seem to lack a historical understanding of bicycle drivetrain development and use as well along with some peculiar pseudo-mystical fantasies.
The fixed gear drivetrain was and still is required for track competition but was used from the inception of the road bicycle and still serves today, as noted in all of the posts in this thread which are exclusively about road FG use.

The Tour de France was restricted to fixed gear/SS road machines from 1903-1938, it was and still is a bicycle race.

"I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"

-- Henri Desgrange TdF organizer (31 January 1865 - 16 August 1940)

Time trials, which take place on the road, were/are a British specialty and were often won by FG riders.
Pic of the inestimable Beryl Burton riding to yet another victory on a fixed gear.

"Mind melding"?
Where has that concept appeared in this thread? A fantasy you have perhaps?

"Grunting?" I think that is common in Tennis not in my experience of cycling.
Riding in difficult terrain on any flavor of drivetrain will take effort, doing so on a FG is indeed satisfying.
Time to go out for an hour or so to overcome some limitations on a FG bicycle ride, as club cyclist have been doing for over a century.

PS: You will have to have "the last word" about something that you have no experience of so: Knock yourself out.

-Bandera