I can’t give you any cites, because I’ve never heard this before.
But, consider this: They were two completely different types of movies, even tho both fit as Sci-fi. ET was a feel good movie, lots of cuteness, major family appeal. JC’sTT was a harsh look at a deadly problem and didn’t even get a happy ending. One was rated R the other, PG. One was hyped by mainstream media, the other didn’t get that free ride.
I think that, regardless of their release dates, the end results would have been the same, as far as box office.
As is often the case in Cafe Society, IMHO, YMMV