[jonathanstrange]

In my experience, academia seems insulated from the "real world", because specialization has increased and (maybe) also the overall scientific literacy in the population has decreased. I might be wrong about the second point, but the first one alone suffices to explain this perception. Even for scientists it has gotten harder to follow what's going on in neighboring disciplines.

In a nutshell, science has become more complicated and generally requires much harder math than it used to. Case in point: Almost everyone can learn the basics of Newtonian Mechanics or Special Relativity, but understanding the basics of String Theory is much, much harder. Our scientific knowledge has grown immensely.

That being said, your implicit assumption seems odd to me. The "general public" was probably never able to read and understand academic papers and folks outside academia never were able to easily comment on cutting edge work at any time in history. (Except for a few very gifted outliers maybe.)