I look back to the last federal election here in Canada - it was triggered by a vote of no-confidence over the budget, and 5 weeks later the whole process was done. the candidates only had 5 weeks to spend money. no matter how much money you are legally allowed to donate to a campaign, the candidate can only spend so much in such a small time frame. It doesn't matter if you're a billionaire or not, it's impossible to garner much influence when the campaign period is so short.
of course, our voter turnout is miserable and the guy we managed to elect is pretty terrible, i'm not trying to say our system is perfect. but the year-and-a-half long campaign with elections every two years just seems so ridiculous.