What owners try to do and what they actually do can be two entirely different things.
Some owners are strictly RL/LoA, HiA, AA, AAA, BL even if that's not the best thing to do. Some owners let SIMMY run their minors. Some owners de-activate a player and forget about him. Some owners start players in AAA because that's where their best coach is. Some owners put a player at a level because that's their plan but have a crap coach. Some owners skimp on training.
In short, dozens of things can derail development. You have to figure out, when you're trading, if the player you want really only developed 5 points in his first season because that's all he's got or if his owner screwed him up. In one of my worlds, a quality owner(or so I thought) left a legit prospect de-activated the entire season. The player wasn't a stud but he could have sat on a BL bench one day. He just got lost in the shuffle.