To be honest, HW is not a real problem: in Quebec, boxing is HUGE, really, more entrance at the gate for some matches than in NY or Las Vegas for some of the big events and we have absolutely no good Canadian HW, at least, nothing that really flashes. Why does it work? There is a few little shows that you can watch for free on T.V and the sports network are covering it nicely, the sport restaurants (like la Cage aux sports) sponsors big time boxing, especially as Eric lucas owns 2 of it and as he did a partnership with Jean Bedard, one of the owner of la Cage aux sports. There is a couple of matches broadcasted for free and the covering is good.
The lack of big HW in the US is easily explained by the fact that it is easier to be financed at school doing some basketball or football so athletes chose that path instead of boxing but as for the interest, the problem is not in the HW, I really don't think so. Make a few more free matches, talk about it in the medias (not only the specialised ones), spark the interest and it will raise up in a matter of months.