I can reminisce the times when it was relatively easy to buy spares for vehicles. If it was from a British owned manufacturer, your car would most likely have a Lucas Alternator and Starter Motor, and either of these, subject to a couple of variations, could be compatible with just about any other car. On top of that, things like electrical connectors, fuses, bulbs etc were all relatively average. Certainly, if you had a Ford; that would have its own variety of electrical equipment, and Vauxhalls would be built in with Delco electricals, but again, these were very standardised, and so they were very interchangeable.
This state of affairs made it much easier for drivers. It also must have made life much easier for Car Parts Distributors, because. One starter motor would likely fit a dozen or more makes by different manufacturers over an extensive range of years. I seem to recall plenty of other things, including Wiper blades, instruments and switches all being similar across a wide collection of manufacturers. Even the old Champion N9Y Spark Plug or corresponding would fit & work the vast majority of cars. A hand full of different oil filters would also fit on ninety per cent of the vehicles on British roads.
Since then, manufacturers have followed the tendency of individualising the components going into their cars. I can appreciate and see the advantage of doing that with parts like instruments & lighting, because these offer a much better quality and aesthetic feel than owning a car which has clearly been produced by purchasing an assortment of average parts & fitting them together. To a certain extent, I can also accept this individualism in components like spark plugs, as engines are becoming much more sophisticated & have much more exact requirements in order to run right and at greatest efficiency.
Having said all that, I’m convinced plenty of items could and should be standardised, but the manufacturers have been following a purposeful strategy of individualisation for a reason, because this is an excellent way to lock unsuspecting drivers in to very high cost replacement components and consumables.
The latest Flat Wiper blades which have appeared on the market in the last few years have been a good example. I heard of one motorist of a German car paying near to eighty pounds for a set of original fit rubber Car Wiper Blades from the car franchised dealer. At that time I could have bought up to four pairs of high performance Silicone Wiper Blades, and had some change, AND had the advantage of the twelve month warranty that comes with many Silicone Wiper Blades.
It can not be beyond the intellect of car manufacturers to revert back to industry standards for things like Wiper blades, Starters, alternators, oil filters etc. They do not all have to be made in one factory, however a standardised design would reduce development costs, improve compatibility, provide more competition & benefit us, the consumers.