The cynic in me assumes the 40% savings will just get shoveled into the F-35 furnace.
Otherwise, yes.
You might be thinking of the F-111, which was supposed to be all things to all services. That was the 1960s. Or maybe the failed A-12, which was supposed to be an attack plane for all services.
But you're correct, unitary, multi-role fighters have a bad history.
Multirole capability is primarily a function of the weapons an aircraft can employ. This wasn't true in the 70s when targeting pods were binoculars and effective employment of aircraft in strike roles required decent performance in low-and-slow flight regimes, but we've been living with pods and PGMs coming out of our ears for 25 years now. Design tradeoffs for multiroles today are primarily those of cost and maintainability. You can pay out the ears and get larger twin-engine multiroles that strain logistics and wallets, opt for a single-engine F-16alike multirole that'll do everything nearly as well except for flying really high and really fast, or inexplicably go Eurocanard to pay F-22 prices for sub F-35 capabilities. Anyway, the point is that it's next to impossible not to make a multirole these days even if you're trying; if you can employ weapons with your jet, you're multirole.
The F-5E/F Tiger [0] was one of the most under appreciated fighters on the market in the 70s and early 80s. The was limited in A/A victories in real combat because of lack of opportunities, although successfully used at TOPGUN and FWS at a low operating cost. Although marketed as a LWF, The F-5 was actually a multi-role aircraft, and used in combat as a strike aircraft.
IMO the F/A-50 [1] is the most under-appreciated advanced 4th gen fighter on market. At around $30m its half the cost of a new F-16, although a refurbished F-16 is viable for budget constrained Air Forces.
You're thinking of the first generation of what became the SR-71, which was made for the CIA, and used a different numbering scheme: https://en.wikipedia.org/wiki/Lockheed_A-12
Similarly, the A-12 was also a Navy program, not a joint project. The Air Force considered buying it (had it been funded to completion by the Navy) as a replacement for the F-111, but this consideration was largely superficial, and they had little to no input into it's design.
Not IMHO: The launch is a single, controlled, predictable task; they can choose their exact launch time and location for optimal performance; have extensive quality control checks and engineering, a room full of support engineers, etc; the exact route and timing of the launch is carefully planned ahead of time, etc.
The plane has to handle every contingency of war: Take off from wherever and whenever needed, fly anywhere, refuel in mid-air, dodge enemies trying to kill it (can SpaceX or ULA do that?), destroy enemies trying to avoid it, return safely home, etc.
And all of those problems are (supposedly) solved by the time the plane is being manufactured.
Your argument regards R&D costs, not manufacturing costs.
I thought dogfighting was nolonger required in this day and age?