Lets look at current Leafs who were drafted by Hunter and Lou and developed by the team.
Auston Matthews,
Mitch Marner, and
Timothy Liljegren. That's it. Others have been traded or claimed on waivers but did at least make the NHL.
Travis Dermott, Adam Brooks, Dmitro Timashov, and
Carl Grundstrom. Goaltender
Joseph Woll played a few games last season, but will start next season in the minors. That's 8 players who have played games in the NHL out of 27 picks across three drafts. Outside of the first round, only 5 of 24 have made it to the big leagues at all, 2 of whom have played less than 50 games. Not a very good success rate.