Honestly, after playing the mode for myself I can pretty much say I think they deliberately did this as they thought people were playing Rtts too much and wanted them to play DD instead. I genuinely can't see another reason to make Rtts so shallow and, essentially, short.
In years gone by, it took years of playing to get your guy to be a major league stud, you had to put a lot of time into it and that was the point, the journey, levelling up and getting better. Then you'd probably do it all again with a different player, go on another journey. It was an RPG. This year it's all pretty much done inside one season, maybe you play a second so you get a full year with your stud in the majors, but I can't see much reason behind playing beyond that with the way the game is now. There is literally no reason to have a second save as your guy starts with the maxed out ratings from your original save.
They've taken away the modes longevity.