Lithium ion batteries and battery modules are never ever gonna be user repairable. The main reason is that the electrolyte is a highly toxic, carcinogenic and extremely flammable organic solvent. AAs are user swappable because the electrolyte is water based.
Bikes started being less repairable when manufacturers noticed that steel frame 10 speeds were lasting multiple decades. If parts continue to be available, those frames are still going to be in use another 50 years from now. Particularly where cartridge bearings are used.
Carbon fiber bikes are part of the trend. Will we eventually see a straight up plastic adult bike frame?
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