Why is it sometimes difficult for people to accept new ideas in science and medicine?

The establishment is run by people that have been promoting ideas and methods for years and often made money from them not to mention pats on the back asociated awards ect. They run the status quo. it is not in the interest of the establishment to change things, and they will naturaly resist for as long as they can.

Remember acording to IBM fully ellectronic computers were a pipe dream. they said this because they did not want to be replaced.naturaly it wasnt long before they were.