well the us licensed it because congress wanted something out of the f-2 program (this was during the hight of the anti Japan trade issues) but it didn't end up being worth much and us companies had to develop there own anyway. And the us was working on aesa on its own and was only behind by A few weeks? I think.
The claim that the F-2 radar is no better than conventional US F-16 radars in performance and inferior to some on other airframes also raises questions about the comparison metrics. It could conceivably be accurate if you narrow your interest to range exclusively - this is mainly determined by power output, antenna size and sensitivity. Early TRMs as used on the F-2 radar would very possibly not have given power or sensitivity improvements, and antenna size is obviously comparable to the F-16 (and smaller than other US fighters).
But that constrained view is to ignore all the other advantages the AESA principle offers in terms of agility and ECCM. Similarly, I'm fairly confident the composites skills demostrated by the Japanese will have been instrumental in their ability to secure very sophisticated and lucrative workshare in this field from Boeing (787 wings). So just because US industry/Lockheed-Martin ultimately derived little benefit (debatable, if you consider the 787) from the tech pioneered on the F-2, the same is patently not true for Japan itself.
Altogether, these sources smack of attempts to rationalize what is nothing but a typical NIH attitude at the core.
