I'd say all of Shakespeare, Jimi Hendrix, LeBron James, Martin Luther King (keep on going if you like) have a form of extreme intelligence not measured well by IQ tests. The kinds of problems in IQ tests are one thing our brain can adapt to solve but humans are so incredibly neuroplastic that IQ is much too narrow a concept to be definitive.
We are talking about general civilization's aggregate IQ though. Sure, there are people too smart or exotic to measure, but that's true on both ends of the spectrum, so might they balance out?
Perhaps, you know, in the past, it was more difficult for those with lower IQ's to survive. Now people with lower IQ's can survive for longer, which is good for them -- absolutely! -- however, it would reduce average IQ's.
That would also suggest, this isn't something bad for civilization like the article suggests. Perhaps the same number of incredibly intelligent people like the ones you mention are better able now in this modern age to get their solutions to more people to make it easier to live.
This is mostly a definition game using "intelligence" to mean "reaching the peak of a narrow skill." That sort of peak takes a tricky-to-nail-down combination of innate ability, practice, and environment to reach. When people are talking about IQ, they use the word intelligence to describe, essentially, fluid problem-solving and reasoning aptitude. A lot of disagreement in this domain can and should be resolved with clearer terminology.
IQ says little about the specific skills someone has trained, so more specific tests are useful for that, but it provides a lot of information on the general aptitude it is intended to assess.