The ironic thing is that moving back to "first to invent" works in favor of big companies who can afford armies of patent lawyers to argue over who was, in fact

The ironic thing is that moving back to "first to invent" works in favor of big companies who can afford armies of patent lawyers to argue over who was, in fact, "first to invent". First to file is much more egalitarian and more favorable to startups, small companies, independent inventors, and suchlike. And yes, I get that "first to invent" feels more fair in a certain sense. But from a pragmatic point of view, first to file makes more sense. It's also more consistent with how most of the rest of the world works, if I recall correctly.