They will have to or they risk losing more players to the KHL and other leagues. A lot of these players consider medaling in the Olympics to be just as important as winning a Stanley Cup. Who would make up the Canadian and American teams? MJs and NCAA players? AHL players? In the middle of those seasons? Even if that did get worked out, the European leagues would still bring over their players, and it would be a slaughter. The NHL has less power on this issue that they'd like, they'll start feeling pressure from IOC, Hockey Canada, USA Hockey, NHLPA, etc. and will cave with minimal tradeoffs.