The old boys network is human nature. Things like that change because change happens. GMs hire the same old coaches because they know them. That is the human side. You see this with employers all the time. Two people come in, one may be better on paper, but the other guy is a known quantity that they can trust to do the job.
The reason European coaches aren't brought in often is a lack of relationship. If you coach overseas you aren't building the network of trust that a GM is potentially putting his job on the line for. For the longest time, there wasn't a tremendous amount of women's hockey. When there was, there was usually a male coach because there hadn't been many female players to turn into coaches. Decades later, there have been many more women players who have turned to coaching. Now there are more options coming available. Jessica's hire probably has a lot to do with her relationship with someone in the org in addition to her resume. We have all known people who have the goods on paper but were a terrible fit at our own places of work. No different in the NHL. It is a relationship network. We are now seeing something that has been slowly growing blossom into possibility. I think it is unfair to just label it old-boys network when forward thinking in a results based job can get you fired fast if your forward thinking will take time to develop or the person just made a wrong choice. GMs will hire goats to coach if they think it will get them championships.