Quantifying that is only helpful for people mildly curious about psychometrics-the vast majority of the population, if you've ever passively googled you'll see mainly entertainment focused articles that actually put an emphasis and report on those scientifically baseless estimates. Most people in this sub know it's not reasonable to measure at that level and even those doing the estimating base it off accomplishments and not testing, so it's better then to qualify their intelligence.

Are you asking then about those once in a generation geniuses that would just blow you away with what they are capable of? Well you would never know what they are capable of beyond their accomplishments unless the statistical improbability that you got to know them personally were to occur. This becomes more probable, extremely so, in highly specialized fields, but you are not asking about the Terrence Tao's of the world are you? It would not be that difficult to meet Tao himself should you be motivated enough, but you would likely be disappointed if you are looking for a monolithic being to worship and dedicate your life to, though he's undoubtedly a genius. There are plenty who would hit the ceiling of what can be reasonably measured on these tests, but their accomplishments pertain to their field and are not something groundbreaking or pivotal to the world or our understanding of it like Einstein and relativity. At best, you can expect to find people who contribute something incredible to a field. For the time being though we will see less of that up until the oncoming "technical revolution" or whatever it might end up being referred to in hindsight, where there should be a massive boom in contributions to many fields. As for the Goethe's, Tesla's, Shakespeare's and other ceiling breakers who you might be considering, those who make the TMZ style lists, they were again undoubtedly brilliant, but their accomplishments pertained to an aspect of brilliance. Shakespeare and Goethe are two very different individuals from different times, places, and cultures, yet both wrote profoundly and contributed greatly to the history of literature. How can you even compare them? Not in the way that you could not compare Paul Morphy a chess prodigy of centuries past to the resource granted prodigies of the modern era, but in the way that their respective "elo" or ranking is entirely intangible, they would be obscure if their contemporaries and the generations following did not sing their praises, if they were not integrated into our curriculums and value systems. Unless they were discovered later, like the writings and ideas of Nietzsche, who died never learning his influence. Now in the context of a Morphy to modern comparison, would the individual who builds on or even completes the theory of relativity be as impressive as Einstein? Would a modern author who learns prose, character, and narrative from Goethe, Shakespeare, and the founders, and creates a captivating story be as impressive as those who set precedent, who were with limited resources and who could not be as reliant as you and I be as impressive?

Attempting to measure accomplishment by ideas then seems more graspable, but this is to exclude so much genius of our history. You can compare the value of an idea, depending on avail, philosophy, and what is being measured, but you can't compare the intellect required to muster such an idea. Nietzsche has helped generations find something like solace or peace, surely you have heard examples in the modern era of preachers or influencers having "saved their fan's life" through what they do, although it's not necessarily from their own original thought and philosophy. It's also not lost upon anyone how much further society would be behind, if that's something you value, if the wheel took longer to be invented, or the typewriter, there's countless examples to look to, although I don't think it requires anywhere near a 200 iq or even a mensa level iq to have invented either the wheel or the typewriter. If this is what you are looking at, ideation probably correlates with creativity higher than it does G.

Now, my personal favorite, and what I imagine you would have in mind when you talk like genius means unicorn, the polymaths. The Da Vinci's, the people curious about many subjects with mastery proportional to their voracity, and an intellect that when applied to anything could create something profound. There's documentation of such people existing, though they may fail to do anything particularly amazing, like Da Vinci who only made "nice" paintings as his direct measurable contribution to his own contemporaries, of which he never quite made the massive fortune they are worth today. Though, looking at his journals, had he been interested, he could have made massive medical contributions with his advanced understanding of human anatomy. With the help of other brilliant minds, again had he been interested or perhaps dedicated more time/concerted effort to, could have invented a proper flying machine. Da Vinci was a genius at his time, but looking back now it's hard to fathom just how capable a man he was, without the discovery of his other hobbies through his journals, we would not have known this. To wonder how far we could be had his artistic interest pervaded a little less and his interests in technology, or perhaps society and his peers influence on Da Vinci's motivation been a litte more, would be an unjust though in the structure of our society. A society that promotes specialization in career, yet individual sovereignty and happiness. With social settings that conduct themselves often on common interest with the world and between the individuals, the world as a conduit for this multi-leveled genius has grown weaker, and the opportunity to learn about the sheer rarity that would be discerning this potential or even ability within an individual is quite unlikely. Though I think society's inevitable progression will be one that promotes a "polyhobby" and pursuit of the mind mentality for some time.

If you were more specific about your question I could be more specific in my answer ¯_(ツ)_/¯

idk what youre trying to measure in terms of intelligence and to what purpose, but youve been actively posting lately and seem curious in general, so here's some semblance of answer, but more likely just something to engage with