https://janheine.wordpress.com/2013/12/06/cycling-under-the-german-occupation/
http://www.dailymail.co.uk/news/art...ch-capital-citizens-thriving-German-rule.html
German occupiers wanted them on bicycles, and certainly production of aircraft grade tubing was a priority, as well as any light metals industry that could also produce aircraft parts and not get bombed.
It worked the same way in England when they were surreptitiously arming before the war, beginning with Armaments Directives in 1935.
E.g. JWYoung & Sons of Redditch were building fly reels with aircraft control system ball bearings to mask the parallel production of aircraft control systems - a crown in my reel collection - a product of MI5 and English bench craftsmanship.
Imagine Paris with no cars.
If you do the math, France was not at war - they had everything except gasoline - and they provided un-bomb-able industry for their occupiers, as did the Dutch and Belgians.
For 4 years, no one in Paris had gasoline (except the occupying army). People still worked, went to restaurants, went shopping for food, clothes - and bikes.
Parisians spent their transportation budgets on really nice bicycles.
Rene Herse and Alex Singer both had French Jews hidden in their shop basements building expensive bicycle frames.
Every day was a bicycle race from Paris to the outlying farms to get produce to markets back in Paris.
And of course, every cab was pulled by a bicycle.
original Herse - 1941 - built in occupied Paris
restored Singer
v. Bartali's 1938 TdF bike
Within an industry, the technology blooms when you pump money into it.
Whether it's military development, consumer demand from need, or the baby boom and following bike boom.
Who ultimately standardized the chain? Handlebar, stem, seatpost, axles... Military requirement for interchangeable parts (the Brits call it duplication) a concept that otherwise didn't exist in 19th century industry.
Is there anything that has come out of racer's edge since the bike boom that you honestly require on your bike today? Gruppo? Carbon? Electronic shifting? - all about marketing.
Aluminum frames? - that's only about cheaping-out on production costs.
Good clinchers? - nope, that's consumer driven, racers are still on Dugast.
The next major step is on its way - e-bikes - driven by transportation need (though a couple of racers have borrowed the technology to cheat)