You can justify the issue as much as you want - for the sake of realism it would be the easiest solution to connect JS and FT skills to produce realistic stats.
As it is now its poor game design nothing more nothing less. A team that improves his FT shooting every season (if you train FT once or twice) is just as unrealistic.
We have an easy fix suggested, yet nothing happens. Thats really stubborn and hurts the game. Same for new teams that get gangbanged by established teams, but thats another topic.
Holla!
Größter Knecht aller Zeiten aka His Excellency aka President for Life aka Field Marshal Al Hadji aka Lord of All the Beasts of the Earth and Fishes of the Seas aka aka Conqueror of the Buzzerbeater Empire in Europe in General and Austria in Particular