Then have they repeatedly fought so hard legally to get to keep extracting three revenue? If they didn't care about it, they wouldn't do it in the first place.

The problem is that there's no pressure on them to act any differently. If they made 100x as much money from app purchases, they wouldn't suddenly treat app developers better just because of that. They might treat them better if the app developers had better alternatives, but that would also be enough to force Google to behave differently even with the current amount of revenue.