The scouts are important employees that have specific jobs to do. My point is every large organization has professionals in place who are expected be masters of particular aspects of need for the organization. For example a CEO or Board Chair, would have less specific knowledge on certain things compared to lets say an engineer, architect, medical director etc. Those positions would be the experts in that defined role with reporting structures to the leadership group. A scouts job is to spend 100's of nights in hockey rinks across NA and Europe and compile information to be used by the organization. They would then report that information to the decision makers through an established structure and be available at certain times to discuss and analysis that information with leadership. Or to seek out additional/supporting information as directed. Ultimately, the person with the authority makes the final decisions. They will take the responsibility for mistakes and the public credit for success.
I think your comparison is flawed, and here's why (I'm also glad you brought up pro scouts).
The role of a GM has a lot of duties, but I think the generally accepted key roles of a gm as far as team building are:
1) Free agency acquisitions
2) Current player contract negotiations
3) Waiver wire acquisitions
4) Trades (player for player and picks)
5) Drafting
There's really no other way to build a team. This is it. My overall point that in team building, the GM has the least direct hands on work on #5. That' it. I find it amazing people would debate me so furiously on that, which, in my opinion, is self evident even us lay people outside the business.
Free agency involves a gm signing professional hockey players already in the business, although there are the rare occasions you can sign an undrafted youth or an ncaa player. For free agency moves GM's do have professional scouts to help.. but because the NHL is widely televised and there's 29 other teams, Chevy and other gms will often see players in person who they want to sign. There's tonnes of video readily available. Pro scouts help here but GM's will often see in person these players themselves and have a big role in evaluating. Chevys signing of Perrault is savvy not only because he listened to his pro scouts, but, also because he likely saw something he liked in him when the Jets played the Capitals as often as they did in the SE.
Current player negotations are almost exclusively the agent and Chevy 1 on 1, and are all on him. Disastrous re-signings like Pavelecs extension are all on him... in the same way a savvy re-signing like Andrew Ladd would be in his plus column.
Waiver wire signings are helped with pro scouts, but, again, like Free agency CHevy himself is much more hands on because he gets to see these guys in the NHL on a day to day basis. He would have to rely on his pro scout on this one for recommendations I think a little more because the guys going on the waiver wire likely aren't getting a lot of playing time.
Trades This one is 80% chevy. He has to broker a good deal. He has to target the right people with the help of pro and amateur scouts. But at the end of the day he is the one pulling the trigger on these deals, trying to manufacture value for our team. Being told who to trade for is one thing, being able to negotiate the deal is another
Drafting The least hands on. He creates a plan for his club, and tells scout what qualities he likes. He has a type of player in mind, but of course scouts are free to make recommendations (I assume) if they see someone who's an amazing player but doesn't quite fit chevys mold. Amateur scouting is all over the place... from the ncaa to the chl to europe. There's so many teams chevy can't possibly do it all himself.. he has to leave the talent analysis to the scouts.
When draft day comes he has a list of players and all the data, totally compiled by his scouts. He then makes decisions he feels are best... but make no mistake that data is compiled for him. It's by far, and I find it impossible to argue with a straight face, the least hands on duty of a GM.