In order to save on costs & to get production going (as well as keep it going) Kaiser-Frazer vehicles were assembled items rather than manufactured like Packards were. This means going to supplier catalogs whenever possible to pick something already in use by others rather than having the item made special for a Kaiser, Frazer or Henry J automobile. That's why electrical parts either interchange with Chrysler Corporation 6 cylinder 6 volt (Auto-Lite) or 1951-54 6 volt Chevy pick-up truck (Delco-Remy). Also why Borg-Warner transmission and overdrive parts are available (the components went into various vehicles of the time and later) as well as brake parts (such as 51-55 Kaiser master cylinders that are same as 49-51 Ford passenger car). And so on & So on.
Of course over time, the prices will go up a bit (compared to when the cars were new) and certain specialized trim bits, etc will not be easy to find. However, this is already happening with other makes including more popular things like 1960's Mustangs, 55-57 Chevrolet & Ford and even 1980's GM products.