It looks like they front loaded the events for this single which would explain why they only ticked along for the rest of the week after that really good first day. Looking at the H!P site though they have events planned a long way into the future, hopefully this isn't the end for this single.
But I wonder if anyone ever makes much money from singles anyway? In the distant past they were conceived as a promoting tool themselves for albums and tours. There's probably a lot of financial risk in paying out the amount they did for that billboard for example, some of the members probably aren't even paid that in a year. They'd basically have to make a dollar on every single sold just to get that alone back.
But yes here I am draining the fun and life out of Idols with ill informed business talk again.