Ceteris paribus, then. On average, a thought experiment along the lines of "what if I poured this stuff on my trousers" is of much more practical use and tells you much more about reality than a thought experiment along the lines of "what if I could ride around on [intangible thing]". The most realistic thought experiments are the ones we do all the time, often without thinking, and which help us decide, for example, not to balance that cup of tea right on the edge of the table. Meanwhile, only very clever scientists and philosophers with lots of training can wring anything useful out of really far-out "what if I rode on a beam of light"-type thought experiments, and even they screw it up all the time and are generally well-advised not to base a conclusion solely on such a thought experiment. As I understand it, Einstein's successful use of gedankenexperiments to come up with good new ideas is generally considered evidence of his exceptional cleverness.

(note: I know very little about this topic and may be playing very fast and loose. I think the main idea is sensible, though)

This is funny. Until I read your comment, I was misreading the original quote; I didn't notice the "inversely" part. I was implicitly thinking that the quote was claiming that the farther the thought experiment is from reality, the more useful it is. I guess my physicist biases are showing.