The browsers could buffer the text in text fields until the field loses focus (clicked another field or submit) or hit enter. It would break search-as-you-type functionality, but not the biggest loss in the world.
But they don't. So I build it (draft system) for my users by saving what they type as they type it, and they are very thankful.
If you would kill my ability to build that feature, then you better replace it with a solution.