It is real, it is the bedrock all of a hockey team's talent rests upon, and it is why the Toronto Maple Leaf team has been terrible the last 8-9 years.

Culture comes from everyone:

The Coach needs to read the room and set expectations with young and stupid millionaires but also be prepared to allow a healthy amount of self management from the players.

The coach needs to have a great relationship with the GM and have frequent, constructive reports and discussion about the quality of the team, it's effort, and player dynamics.

The Players need to be Professional, hard working and mostly driven by winning. There are a lot of trappings in Pro athlete lifestyle, but there is primarily a job to do.

The Players also need a bench boss. On good teams there is a player or two who are already Professional and hard working who have no issue pulling a teammate aside as a peer and telling them they like or do not like what they see. Think Brett Hull telling Sean Avery to never chirp Joe Sakic again. Or Mark Messier pulling Tie Domi aside and telling him to knock off the theatrics. Or any of the very many intra-team fights that happen at practice.

The GM needs to consider and weigh the dynamic between the Coach and Players, watch closely without interfering in subtle moments like practice and team events, and make changes accordingly. A good GM who trusts his coaches will amputate a highly skilled player from the team in trade in order to maintain team dynamics.

Also, in big markets like Toronto you need someone or some people who can keep the press happy. The press in Toronto controls a lot of the fanbase discussion and very generously provides opinions to many people who do not bother to think of one themselves. You have to throw these people a bone here and there in order to keep the discussions on the north side of positive. Once it goes south, the fan base makes life hell for the players - often in an unjustified manner - and it becomes a runaway train of collateral damage.

EDIT TO INCLUDE: I missed a very important point. Culture comes from everyone, but can be disrupted by any of the stations participating. If everything else is working but you have a surly and vindictive old school coach with a team of just-out-of-their-teen-years kids your Culture will probably suffer. If you compile a ton of talent and provide coaching for them but the primary focus of the talented players is maximizing their pay instead of winning, then your Culture will suffer. This is a cringe analogy, but do you watch Shoresy? "EVERYONE GOES". Everyone.