As to Asimov, yes that's a valid point. He was writing far outside his field.
When Asimov wrote a book on anything, be it Shakespeare, the Bible, or physics, I expect him to have more of substance to say than most experts in the field. He wrote a series of books on physics that are still used today, and he was a biochemist.
SIAI benefactor and VC Peter Thiel has an excellent article at National Review about the stagnating progress of science and technology, which he attributes to poorly-grounded political opposition, widespread scientific illiteracy, and overspecialized, insular scientific fields. He warns that this stagnation will undermine the growth that past policies have relied on.
Noteworthy excerpts (bold added by me):
In relation to concerns expressed here about evaluating scientific field soundness:
Grave indictors:
HT: MarginalRevolution