Has anyone ever been concerned that making their bicycle ride and function better detracts from its historic value - rhetorical question.
You can apply the same logic to automobiles - has anyone ever been concerned that making their car perform better does the same.
1977 Raleigh catalog.
Anyone who left their bike in this condition didn't ride it.
The "Brooks" saddle was metal pan and padded. Anyone with self respect left it in the bike shop and rode out on an Unicanitor saddle.
All the DOT reflectors went the first day.
The "safety levers" were another sign of the uninitiated, and you'd be searching for gum hoods.
If you climbed hard on the splined crank, it stripped - mine did, the 2nd year.
After not too long, it looked like this.
Amateur racers just about always work in bike shops, win parts instead of money and, if they don't improve their bike with the parts, they sell them in the bike shop. The bike above has that stripped crank replaced with a Sugino Mighty Comp. A new wheelset built on Zeus hubs with Rigida 1320 rims, a tighter Suntour freewheel, and a Shimano 600 RD because the new freewheel doesn't need the chain wrap of the Raleigh-branded Suntour VGT.
All the parts were bought from UT Co-Op Bike Shop employees who had scored new parts to turn in the bike shop, and improved this bike going into the '80s.
This '90s update in the photo above has a Concor saddle and LaPrade seat post - also slightly larger 1-1/8" tires compared to the '80s 1" Contis.
Where's the bike going 20 years later?
One serious touring bike that will climb an 18% grade - i.e., climb anything in the Texas hill country.
Is it worth less than catalog condition? Certainly not to the person who rides it, and wouldn't sell it, anyway.
(the answer is no - it's worth 4 times the catalog-condition bike)
I'm going to add that my friends with vintage and antique vehicles are always upgrading to modern aftermarket systems that make their vehicle go better, stop better, run longer and more reliably.
The improvements don't detract from the value of the vehicle - it's the opposite.