It is quite easy to see why innovation is slowing down in many academic fields,
as compared, say to the sixties. The sixties were a time where the population of students
increased a lot in many countries, and so the number of teachers in university increased
accordingly. In higher education, teaching positions come with research duties and so
the number of people doing academic research increased pretty fast. 
China is a country where this phenomena is taking place at the moment.
For many other countries however, this is over.