The example I used was the Swiss Army Knife. IMO there is no better multi-tool pocket knife on the planet. The original maker of the multi-function tool is the Swiss Army Knife. But that said, the Swiss Army Knife, as good as it is, does not replace a large toolbox.
The screwdriver on the multi-tool is pretty good, but you ignore it if you have access to a purpose built screwdriver. The same with the other functions. My Swiss Army Knife turns into a descent set of pliers. But they aren't as good as purpose built.
So something designed and built to do one thing will always be better than something designed to do multiple things. That is a given.
The A-10 is designed to go low and slow, turn tight at low speed and low altitude, and carry a lot of ordinance. The F-35 is designed to go fast, and carry a small amount of ordinance in hidden compartments. So it would take five F-35's to carry as much as one A-10 and that doesn't include the gun the aircraft is built around.
Remember, the A-10 was designed to replace the A-1. The Skyraider was a propeller driven airplane that we were using in Viet-Nam to attack ground targets. We discovered a long time ago that fast moving planes did not do the job as well as slower moving planes. The Marines had great success in Korea using a World War II plane, the F4U Corsair. This was the era know as the dawn of the Jet Age, when F-96 and Mig's battled for control of the skies. The F-86 was designed for that role however, so it did a pretty good job.
The F-15 was designed as a long range air to air interceptor. We now call such things Air Superiority. The F-22 was designed to upgrade and replace that aircraft. No problem, and Supposedly it does a good job. But the F-16 was a bomber with a secondary role as a fighter. The F-35 is a aircraft that can be made to do everything. I love my swiss army knife, and I'll never give it up. But I'm not throwing away my box o' tools because I have one.
= new reply since forum marked as read