Edmonton is the closest large population to Valemount and it is probably about a 6 hour drive in winter. And while Valemount is farther from Edmonton than Marmot ski area (Jasper), it is closer to Edmonton than Lake Louise or Sun Peaks which normally do get some Edmonton skier visits.
Edmonton is the gateway to the Alberta oil fields, so while some real estate sales to Edmonton skiers is possible, the current depressed price of oil has killed oil exploration and likely purchasing of second homes by many Edmonton skiers along with it.
As far as an international airport for Valemount, to sum up Albertaskigirls early post: It is not going to happen.
The regional airport in Kamloops (under an hour from Sun Peaks) can handle jet aircraft and services about 150k people in the immediate region and while the building of Sun Peaks has caused an increase in air traffic, there are still no direct flights from Canada's 2 largest cities, Toronto and Montreal. There are a noticeable number of Seattle skiers who have second homes at Sun Peaks (about a 6 hour drive) and a few years ago Sun Peaks paid a subsidy to Horizon Air to provide winter time flights out of Seattle to Kamloops. It was not sustainable and was cancelled after a couple of seasons. So even an expanded regional airport for Valemount is probably not viable or the expansion will be linited and not able to deliver enough skiers.