Air combat is rarely 1vs1 so being slow means you get killed by someone else.
Air combat is rarely 1vs1 so being slow means you get killed by someone else.
Even beyond that, the general impression I get w.r.t stuff like supermaneuverability is that it's a much better use of money to ensure that most fights never even make it to the point where the stuff like the cobra seems like a good idea. Given the choice between 1) "marginally improving survivability in comparatively low-energy corner-case states" and 2) "increasing the odds that the fight never makes it to the merge," #2 seems like a much better choice in terms of money spent and pilots kept alive. (Though a counterpoint, I guess, based my my casual understanding, would be that making the judgment too heavily in favor of #2 was part of what hampered the USAF and Navy's air-to-air combat capabilities in Vietnam)