> back then they argued that missiles had eliminated the need for agile fighters, but the Vietnam War's rules of engagement meant that agility was crucial.

Please stop this. Vietnam era missiles were little more than firecrackers with IR seekers that flew into the sun. That's why pilots needed their guns, because guided missiles were so shitty at the time. Modern missiles are basically immune to passive countermeasures and have directed warheads, thrust vectoring etc. and would be the first choice of any fighter pilot interesting in staying alive.