The Montreal Impact has always had their 8000-10 000 hardcore fans in the city for professional footy, regardless of the level. Some argued that for the football club to be taken seriously on the pro sports landscape in Montreal, it would need to play in MLS, the highest level of soccer in North America. Ironically, years after the inception of the MLS, Montrealers were told by journalists and people from the Impact that there was not that much of a big different between MLS and USL soccer. Upon being awarded the 19th MLS franchise, the Impact expanded their stadium to welcome additional 7000 fans. As of July 11th, the side has not been able to sell out the stadium, even with new pricing packages.
Both sports franchises must be repeating the same statement as coined by Babu. The issue is simple. There are not enough hardcore football and soccer fans in Montreal that will show up regardless of traffic problems, ticket prices or whatever the excuse is convenient.