I agree, but those who train young players can afford to lose training weeks when they can train more important skills.
Here's a concept that in my opinion would be the best and most logical - FT related to JS. It's very reasonable that a player who has JS 15 has at least 6-7 FT. It's absolutely stupid that he can't hit a free throw but hits 7 of 9 jump shots during the game. When JS pops, FT also does, but in lesser degree. However, for those who want to get faster FT ups, the option to train it independently should stay.