See F-4 and F-35 for proof of the principle. If you make something that has to a hundred different things don't be surprised if is very expensive.
The US DoD will never learn. Build something for a single purpose you get it faster, cheaper and it is usually pretty good at the mission, see B-52, A-10, F-16 or F-15. Build it for a single mission then maybe modify it for additional missions afterwards