Last week, Microsoft held what has become an annual event for the company, a fall showcase for its latest Surface devices. The widespread praise that greeted the new products was a pinch-yourself moment for those of us old enough to remember when Microsoft didn’t make computers and was often blasted for its bad design taste. 

But what is Surface for Microsoft? 

Microsoft CEO Satya Nadella says Surface is an attractive business in its own right. Perhaps more importantly, though, he says Surface’s innovative designs serve as creative beacons for independent manufacturers of Windows PCs. That, in turn, should help drive more sales of PCs and the copies of Microsoft software that run them. The numbers, though, suggest that’s not happening.