Hi Lee,
I agree. All mechanical things like binoculars become obsolete and unrepairable but with care they can remain useful.
For a about 7 years I happily used a
Leitz 7x42 Trinovid BA binocular. It was made in 1983. (As you know its Uppendahl Roof Prisms did not have phase coatings.) I got it new for about 1/2 price from a Canadian Dealer after it was discontinued in 1990.
I used it all the time. I thought it was great binocular! And it was, compared to the ones I had been using. It has a big 7mm exit pupil, long comfortable eye relief and a bright clear view to the edge of its 8º FOV.
I wore out one set of eye cups over the years I used it. They were the Screw on type and I was able to purchase new eye cups because Leica (The Leitz name was now history) still had some left in stock. I still have them on the binocular.
When
Leica discontinued their 7x42 Trinovid BN around 2004 I purchased one from Cabela's at a sale price of $799.00. (The first time I used it and compared it with my old Leitz 7x42 I was stunned at how much brighter the Leica 7x42 Trinovid BN it was than my old Leitz 7x42 Trinovid BA.
Here is a picture of it from Allbinos:
https://www.allbinos.com/1653-Leitz_Trinovid_7x42_BA-binoculars_specifications.html
Here is the one that replaced it:
https://www.allbinos.com/628-Leica_Trinovid_7x42_BN-binoculars_specifications.html
Bob