There are also a number who won't take the chances to come over to NA. Especially in the coaching realm. With refs/linesman... it is honestly pretty simple. The pay is not nearly enough to make the jump, and to get a full time NHL gig... you're in the AHL typically for 4-6 years with zero guarantee you'll move up permanently. It isn't worth uprooting your life for that grind.
ROI is incredibly important here. This isn't an established venture where there is prestige in ownership, nor is there return simply based on scarcity (how many NA sports teams operate). This would be an all new venture with a very significant risk of failure. Especially if you're targeting cities that have very little established hockey fandom... like Milan, Paris, London, and Vienna... arguably even Oslo and Copenhagen. There needs to be light at the end of the tunnel for billions to be spent. As a league, the NHL isn't so flush with cash that they can as a group afford billions in a venture like this. European owners simply have a different outlook as well.
As for competing with the KHL... you have to be attractive to get players. If the KHL is paying double, what is the reason to go to this league? The paycut (compared to KHL) and chance at the NHL is the AHL route as built in now. You have to pay and build in the best chance.
IMO the biggest knock on European prospects is not the style of play. Plenty of players are adaptable. The bigger knock is they are not always willing to put in the development time and earn the roles. They want NHL or back home... this would arguably make that issue worse. Even if you could call them up, they wouldn't be ready in a matter of hours... we're talking days if not weeks considering the visa and tax issues surrounding it. But why would a Swede stick around in the AHL for a year or two if they could just go to this league? How would they earn their roles when the callups would be significantly more difficult?
I would like to see a better and more unified European league, but the business case for it is incredibly difficult. Without a business case, you need prestige and status... which this clearly wouldn't have.
For sure the player transfer timeline is the biggest drawback to being an AHL equivalent; but the mid/long-term player development would be better.
Currently the NHL loses those players to the KHL for multiple years, so having them "in the pyramid" is preferable. I think many players and coaches in general would love to leave the KHL and the political/authoritarian structure there if only there was a decent alternative. With the decline in the KHL this is the perfect opportunity for the NHL to lead the way and gain the market share. It will pay off in the future.
The other Euro leagues all have caps on "foreign players" that I would not want this league to adopt to encourage broader scouting and team construction. The Euros that leave the AHL to "go back home" would be offset by many North Americans staying home to play in the AHL.
Every year the NHL pyramid loses quality players back to Europe never to return because these guys don't want to be paid peanuts in the AHL far from home; but the quality of play in Europe isn't sufficient to help them establish NHL value.
As far as playing style, guys like Juraj Slafkovsky were not prepared for the physicality and smaller ice surface (reaction times) despite strength/size. It is a different game and it does take longer for players from Europe to adapt to the NHL. A select few (growing now that the CHL increased the import player limit) of junior players take the chance to come over for their development but those are a small %.
Each European team would operate like an independent AHL club with player assignments coming from different NHL organizations.
The ticket gate revenues would be enough to support the player salary budget.
36 home games each x $35 (USD) x 5,000 Avg Att = $50,400,000 subject to each market's demand.
Concessions, merchandise, advertising would contribute to arena/operations costs
The NHL would subsidize the executives, coaches, referees, scouts, etc.
All media rights/ content distribution would flow back to the NHL (this would have the most long-term value).
If the NHL is going to be expanding to 36 teams (likely at this point) then this league would help the dilution in North America by not needing any more AHL expansion. Enough roster players could be assigned to Europe to offset it; along with adding back high level players into the NHL pipeline away from the KHL and other European leagues.