Who said anything about no grunts? Its not an either/or. Doctrine is integration, not exclusivity. Also, a true ground support aircraft like an A-10 would probably get picked off in a big hurry by any credible fighter. These aren't fighters. They are what's known as Attack aircraft. Thus the A instead of the F. They don't even have the proper electronic warfare suite for meaningful air combat. A fighter-bomber is an actual multirole aircraft. An A-10 shooting down a fighter would be quite a feat. Its never happened. Pretty sure they've taken down a few choppers though.
As for 21st century aircraft...these are useful for fighting other powers, as opposed to continuously bombing sandbox countries who pose little real threat to us.