A thought experiment with no wrong answer I think, how is "success" measured in this new world by the parties involved?
Everybody's talking about this new "CHL-NCAA-NHL" pipeline but that's not going to be the case for most players. There are going to be plenty of CHL players who's hockey career outcome is going to be essentially no different than the USports path of years prior. They'll play out their CHL eligibility (to 19 or 20), then play out their NCAA eligibility, get a degree and go on to the rest of their life or they'll sign a Euro or lower level pro deal.
If a hypothetical example player named Kavin McGenna plays for Quendelton State University in the NCAA for his draft year, Quendelton gets announced on draft day but McGenna would probably still be in discussion for #1 even if he didn't play hockey in his draft year. Is McGenna a NCAA success story or are they just the league he happened to be in as he crossed the hypothetical finish line of development from junior team(s) prior? Both places will consider them a NHL alumni though.
I definitely think CHL teams would be and are considering the departures of their unsigned/undrafted overagers, or soon to be overagers, to the NCAA but we'll have to see what happens when it's not those players.
Like I said at the top, I don't think there's a wrong answer but I definitely think people need to temper their expectations about future NHLers when posting every single CHL commitment.
Yes, bit of a tough question to answer directly and one that largely gets to the heart of many discussions around CHL vs. NCAA, whether to go to the NTDP, how the USHL should operate, different development paths, etc. that flows down all the way to younger ranks when families with players as young as 10 start considering moving around for their hockey "careers" in order to maximize chances of a professional career (not just in North America btw).
When Connor McDavid first enters hockey with all the various other kids, it's not like all the kids are the exact same, and McDavid gets the magic hockey development dust sprinkled on them and then come 17 he's the first overall pick. From the moment he first stepped on the ice, he's going to be way better than every other kid that also stepped on the ice, by a wide wide wide wide margin. While some kids are late bloomers, many will follow such a similar story. Every time they step on the ice, they are better than everybody else.
While we know he won't go from first stepping on the ice to being the best player in the world automatically, it is difficult to say the level of "credit" any specific development path along the way played in becoming the reason. At that point, he will likely follow the same path all the other great players did before him, not because we necessarily know this is what produces players better than any other hypothetical system could, but more so,
we know at the very least it doesn't harm them. If it worked for Crosby, worked for Lemieux, worked for Gretzky, worked for Orr, then what we can almost certainly say is that "if it doesn't work for McDavid, it's probably not because of a bad development path, but some reason personal to McDavid".
In truth, we could probably surmise that as long as a talented player like McDavid (a) is on the ice regularly, (b) participating in hockey drills and games regularly, (c) is continually being moved up and challenged with increasingly better competition, (d) has a good work ethic and attitude, (e) has favorable genetic results as he grows in terms of his height/build/physical characteristics, etc. then it probably does not matter so much if he had gone one particular "development path" versus another.
Of course that won't stop every person he encountered along the way from taking some degree of credit to say 'see, look what I did, I created McDavid!' like a Frankenstein's monster built in a lab, as a way to advance their own interests. When all we can truly say with any degree of certainty is "well you didn't screw him up at least".