I think the quality issues are more a function of surging demand than simple lack of overall quality. When there are orders to fill, a manufacturer wants to fill them. Sometimes when the demand gets really high, some manufacturers push back delivery dates. Others rush things, delivering products that may not have been properly inspected, or (shudder!) lowering standards to meet demand.
In this case, I think that Asustek has simply rushed production, leaving less time to inspect and test for errors. It's not like there's even a high percentage of failures in logic boards. There are some failures, but we hear about them because they're so exceptional.
I'd love to see a real analysis of the failed units, when they were ordered, and what the order volume was when they were built. It would be enlightening at least.
BTW, Asus PC products are not "bad," merely around mid-range. There are several PC motherboard producers that make Asus look like Cray! Price is seldom a real indicator of quality, especially when features and track record are taken into consideration, and that is exceptionally applicable in the computer business.