I'm not claiming fixed is better overall and wouldn't want to just have a fixie, though my proper geared bike has languish in pieces for the 4 years since I got the fixie, but that's just procrastination.
Just because I struggle to describe in words the niceness of riding a fixie, doesn't mean it isn't tangible. I fully acknowledge this might not be valued by others - who naturally enough would prefer a freewheel and gears. Personally if I was to sacrifice the fixie benefit I'd want gears rather than have the worst of both worlds of single speed as it were. Fixieness clealry has a considerable disbenefit of having to pedal like buggery down hill for a start, as well as the lack of gears shared with a ss.
Not sure what a good analogy might be in another field. Maybe a musical instrument - my professional standard "new" french horn (40 years old 2nd hand) is objectively easier to play and gives a better sound - but it's also "nicer" to play - which I'd be hard pushed to describe properly
This is fun! I enjoy debates like this.
I agree, riding a fixed gear bike is completely different to riding with gears, and that dichotomy of experience can sharpen the mind and enrich the cycling palette.
I will say, though, in contrast to what you said at the beginning about your fixed gear bike, if I could only own one bike it would be a freewheel singlespeed.