There are surely such individuals alive today and others that have been between now and then. They may not be as visible or, if they are, are rarely presented in the same domain as leonardo. I think it's better to say that no one alive today is as fetishized for their multi-disciplinary capibility as Da Vinci.
It's also not hard to argue that we have more surface area for innovation today as well a society that offers the 'resources' (i say this broadly) for individuals to pursue explorations and discovery.
But do you honestly think there are individuals alive today making extreme broad breakthroughs like Isaac Newton?
Part of the reason I believe previous scholars were so successful in coming up with a plethora of ideas is that it was easier to observe things. For example Galileo just needed some really good glass aligned properly to see planets but today the amount of manpower needed to see into the cosmos far exceeds a single individual and their budget. To detect neutrinos required a multi story tank filled with water with extreme precision instruments. Meanwhile Newton took some glass (glass was damn useful back then... it was like the computer for innovation) and noticed light could be broken into colors.
Like I said earlier I don't know how you can place the value or rate ideas but please point out some individuals making cross disciplinary breakthroughs at the level of Newton today. I'm actually sincere because I would like to know more about these individuals.
"If I have seen further, it is by standing on the shoulders of giants."
Scientific progress is incremental it builds on the work and ideas that have come before.
yeah, it's not obvious that the thesis here is true, in fact I would suggest that its probably not true
the surface area of new idea is probably expanding, and the resources for finding new ideas is almost certainly expanding as well
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seems like the better argument is that ideas in the future will be in different idea spaces than the current ideas
and that within a specific idea space, you can exhaust the ideas
In fact, in that video Kay compares da Vinci to Henry Ford. Ford was hardly a scientific or design genius, but he had access to the right equipment and had a much greater impact on the world than Leonardo.
I sort of came to the conclusion that the paper proposes... new ideas are harder to find. To really make a breakthrough in a field seems to require intense specialization.
It is sort of sad because some of the greatest innovators have traditional started in some other field and often use the power of analogy thinking to come up with new ideas.