Duh...why would they? Why help their competitor?

What you seem to ask for was sort of provided by the Sutherland Manual back in the 1970s-1990s. But this type of data center requires a lot of energy. Human, financial and social. As the industry became more global and the pace of change quickened further the ability for a central source of data to be even just behind current became harder and harder to accomplish. Who will pay for a third party to do all the testing and compatibility testing? Most any manufacturer won't want to support their competitor's product and accept any potential liability that could be claimed. Manufacturer will keep their instructions/compatibilities between their own products. (The major exception to this I know of is SRAM's Grip Shift line has had Shimano specific/compatible gear indexing, but those two companies have some court history between them...) Andy