They didn't shot down the drone, they hijacked the command link and applied GPS jamming to bring it to Iranian territory.I am very proud of TUSAS. Congrats to all.
But:
"If best America had was not stealthy enough even for Iran, what is the point? " Is there a constant program scientifically evaluating our planes against various air defense radars to figure out weaknesses as in the movie "broken arrow"?
Currently stealth is a very capricious tech as I understand it. One day your plane is stealthy as it can be, next day a screw is 1 mm off and you are as big as a barn door on enemy radar. But will we even be aware of that before it's too late?
https://en.wikipedia.org/wiki/Iran–U.S._RQ-170_incident
Both of those have their counters now. It isn't 2011 and we are not that cocky with our platforms, unlike the US.