Don I couldnt agree with your reasoning more. Sorry for the late response, have been hard down for a few weeks.
The electric clocks do fail...thats why I had to replace mine. The quality of the old clocks is really amazing and as I remember my old Carrier flying days...we didnt have any of the fancy equipment we fly with now...but what we did have you could take to the bank. Whiz wheels and wind up clocks were and are an absolute failsafe for calulating fuel burn. I set the clock, wind it and set the alarm based on a visual preflight inspection of the tank Im burning. The fuel guage is used as a back up. Only human error can screw this up. And by the way.it looks great in the panel.
I bought mine from Duncan Aviation at https://myduncan.aero/online/components ... 010ET.html
and paid 75 bucks for it.