I’ll bet the majority of McLaughlin record sales were like that. People buying because critics praised the hell out of him, only to find that there’s no there there.
Zappa too, IMO, a guy who made a career on marginalia, tuneless weirdness, and a cult following of critics who talked themselves into believing that only they had the proper erudition to appreciate what normal people recognized as pretentious junk.
OMG! Zappa was fantastic! Probably one of the finest shows of mylife! Stanley Theater, Pittsburgh Pa 1976.
Now there's one artist I didn't follow, just because the critics told me to. In high school (69 to 72) I didn't know anyone who listened to him, and the local rock stations only played his stuff on occasion in the wee hours of the night. It wasn't exactly easy to become exposed to his music, because it had little commercial exposure.
I finally did buy one of his later records in the mid eighties. I think it was 'Zoot Allures', from 1976. There were some catchy tunes on there, but in listening to it, I could see why Zappa never caught on in a big way, commercially. His was a unique brand of quirky.