The Q has certianly struggled to produce high end prospects of late, but that doesn't change quality of compeition at present time.
The Q does a good job and poaching talent from other leagues, they have some quality overage talent and have for some years now, the physical difference between a 20 year old very good Junior player and a 17 year old with NHL upside can be quite drastic. We used to routinely see Russian teams that were primarily filled with mid-low ceiling players compete at a high level in the world Juniors year after year as Bragin put a primary emphasis on the tournament being almost exclusive to 19 year olds(obviously there were high end exceptions)
Most of the names you mentioned were mid-late first round picks, didn't exactly dominate the Q during their Draft years.
The key regarding scouting is actually projecting who is not necessarily the best player right now, but who will be superior down the line as well as who plays a more translatable game, the latter is where the Q has struggled, in the grand scheme the overage players and their physical edges won't matter, but at this particular point and time regarding present competition, it's absolutely relevant.
When it comes to league strength the Q is doing quite well due to it's strong influx of overage talent, but there is no denying it's struggled to produce quality NHL prospects of late.