You know what it really is?? They've been SO BAD for SO LONG that whenever they have a prospect that could even be just good- not great- it's so much better than everyone currently on the team. So naturally, that prospect could be the best player on the Leafs in a few seasons. When they throw these kinds of guys into hypothetical trades, they ask for the moon, because- face it- you'd ask for the moon too if you were trading your franchise's potential future.
But- like I said earlier- their perspectives are skewed because they roll out an AHL caliber team with AHL caliber players every year. A prospect grading out to be their best player in a few seasons would be a 3rd, maybe 2nd liner on any team that is even close to .500