I don't think you have a damn clue what "time and time again" means.
Kevin Love threw up over 500 threes the season before he joined Bron. He's averaged 400 threes/year with Bron. And only about 1/3 of those are corner threes....but it's worth noting that he hits those corner threes at a much better rate than he hits his other threes.
Bosh made less than 10 corner threes/season in the four years he played with Lebron. Bosh only made 37 threes TOTAL in his first three seasons with Lebron. He doubled that in his 4th and final season (still making less than 1 three a game)...then proceeded to actually shoot them at a greater clip after Bron left, averaging 1.5 threes/game the last two years of his career.
And that's it. That's the entire list of "time and time again" that we've seen of big men shooting threes with Lebron. One super-prolific three-point shooter who continued to shoot them alongside Bron, and another guy who finally really developed the shot in his final season with Bron but took advantage of that new skill after Bron left.
Meanwhile, Z, Gooden, Varejao, Wallace, Shaq, Joel Anthony, Haslem, Birdman, Mosgov, and TT all proved that Lebron can play alongside a big without that big putting up threes.
Chris Bosh's issue is that he was the 3rd option alongside two great scorers - he played his role great, it's just a reduced role. Love's issue is that he doesn't have a dominant go-to game inside, so hitting threes is literally the best thing he can do to help the team (Love still shoots more twos than threes, but he has really shytty efficiency there for a big man, only shooting 47% on twos.). If Lebron was paired with a guy who could dominate inside, he'd use them inside...he just hasn't been paired with a lot of those.