[Siegmund]

I can read your question two different ways.

The average person knows a tinier fraction of all human knowledge than ever before, because there is so much more information.

But if you're comparing how much the average person knows with how much the average scientist knows, the gap is tiny compared to what it once was. There is a huge gulf between illiteracy and success in high school algebra and chemistry - and then it's possible, if necessary, to explain most modern scientific things in terms the bright high school student can understand, even if he can't do his own research.

Private people doing their own research, incidentally, enjoyed another huge explosion as powerful home computers appeared... a lot of the results in, for instance, cellular automata, did not come out of PhDs. It has slowed a bit as a lot of the old research questions that required nothing but extra computing power to solve have been taken care of - and as computers have gotten complex enough that their full capabilities are a bit daunting to master.