I agree a 100% that more must be done for gender equality and that gathering more data to understand wage gap mechanism is needed.

That being said, and considering that a part of my job is to help gather data from 50+ différents sources with diferent data models, I can agree with google on one point. Gathering data from one point going forward is easy, gathering historical data from a system not designed with logging in mind is a huge pain.

As is usually forbidden in most democracy to issue a law with retroactive effects, it's maybe not a good thing to expect that retroactive dataset should be mandatory. That more of a work for historians and social-science researchers.