Absolutely. The argument wasn't that they're exactly alike, it's that they're related. And I would argue that they're the 2 most related skills of all the trainable skills. Because of that, my other point is that it makes a lot more sense to get a secondary pop from jump shot training with free throws than it does some of the skills that do.
I know Crazy-eye said that you CAN jump when shooting free throws, but when was the last time you saw that? Last time i saw that in a game, I was 9, player junior basketball.