While Rare has had little retail success with its disc-based games since being acquired by Microsoft we now know that they've broke even with at least one game - Jetpac Refuelled for the Live Arcade. In this article at GamesIndustry.biz Rare's Nick Burton expounds on the topic of Live Arcade economics:

If you want to measure it in success in that we broke even - we're in the black, so that's good.

But Live Arcade games tend to sell for a long period of time... You don't tend to get the same sales with Live Arcade that you do with an on-shelf product. There is a tendency to drop down to a few hundred sales a day, and then just stay at that for as long as [XBLA] hosts it," Burton said.

So then you have a guaranteed - small, but still reasonable revenue stream that's constant."

Reasonable enough to make up for all those unsold copies of Grabbed by the Ghoulies? Probably not.