GCN also had good software sales. They weren't quite Xbox levels and weren't really close to PS2 levels, but they were certainly much, much better than PS3's are at this point in time.
Yeah, I also don't think Nintendo would stop producing GBAs for the moment since they're still selling 150K a month, that's a lot of money. Especially when they can't meet the demand for the DS. It's not like Nintendo can shutdown the production lines for the GBA chips anyway, since every DS has one inside, right?