Fairly sure Fleming didn't have anything like the distractions around now when he developed penicillin nearly 100 years ago! The other examples seem to be very much group efforts, and I'd be impressed if the average guy or girl on the street could name the key figures involved. It's possible we've simply reached a point where all the breakthroughs that realistically could be achieved by individuals have already been made, or that in the world of art there's simply too many artists able to readily share their creations with the world for individuals to stand out to the degree great artists of the past did. But I honestly don't know - it just seems that with so many more of us with access to resources and levels of education prior generations could only dream of we should be able to achieve a lot more than we have been.