If we're talking of post-1986 then you sort of have a fair point. My objection, or rather observation, is that your criteria of Norman Orborn and The Kingpin are figures who only became really dangerous when they found out the secret identities of their opponents. As that makes it more than just a professional adversity and hatred, and moves it into a very different personal and vulnerable area for the hero in question.
Luthor was set up as potentially being such a figure very early on, in Superman #2, where he comes within a whisker of learning Superman's secret and his targeting of his parents and Lana Lang puts Superman in just the same predicament and personal hell that both Peter Parker and Matt Murdoch had to endure at various points. When a particularly dangerous and powerful villain such as these learns 'the secret' they are instantly moved into a whole other category of dangerous villain, and to some extent this is where Kenny Braverman/Conduit entered into in 1994 as he targets the life of Clark Kent to destroy both Kent and Superman.
Ever since Superman #2 that fear, of the potential power of Lex Luthor to ruin him in every personal way by remote, unprovable, impersonal means, is a large part of the dynamic that powers the silent war between the two - Superman frustratingly can't touch Luthor. But Luthor could very easily ruin Clark Kent and his world, If he ever even suspects the truth... and yes, there is more than a whiff of Frank Miller's powerful influence on this revised dynamic between the two of which Byrne and Wolfman initiated lo those thirty years ago.
Luthor though is not like the Joker, as he is much more like a Dr Doom, so while he is scheming and plotting always to try to take down big blue, its not as in just killing him off, but in lets get him to be forced to admit that Luthor superior to Supes, just as Doom wants Richards to amdit that!