Often people who are critical of whether AI can lead to research breakthroughs are experts in the respective area, who nevertheless are afraid of their future career prospects in academia (getting a permanent position in academia is hard and it is deeply political who gets such a position).
This people are thus not scared by AI per se (it's basically their daily job to devise innovations that advance their field), but their fears are that
- because of the hype around AI the research into which they invested years, often decades, will be considered "unimportant",
- incompotent people in decision-making positions will think researchers can be replaced by AI.
This is a certainty, not a fear =[.