So much of academic life revolves around bringing in grant money. This is particularly true in STEM fields and at the best research schools. There are ever increasing administrative hoops to jump through to bring in that grant money. And grants nowadays are often given out for research on very specific topics often chosen by bureaucrats. These topics are, almost by definition, not innovative. The NSF is an exception but there are very few NSF grants given out, relative to the number of researchers. My assessment is that the most famous, most published researchers can still afford to explore, if they have the time and inclination, but the rest cannot.