The thing that really doomed the PC market was not that the easy margins went away, it's that OEM's responded by making their products worse. They cut hardware quality, they bundled crapware. The PC experience got worse year after year. Truthfully, windows 8 did not help, but I still think that if the OEM's had just bundled touch screens across the board it would not have been such an outright disaster. The reduced quality forced people off the platform, to macs at the high end, and to chromebooks at the low end. Granted, mobile would have always caused PC sales to decline, but not as much as they did. It is only recently that the OEM's have started investing again in quality hardware with a pure windows experience, and unsurprisingly last quarter PC sales went up YoY for the first time in five years.
When Apple started kicking butt in laptops by using sealed batteries with substantially more capacity, PC makers were locked out from doing same for years because it required battery conditioning software drivers, which MSFT didn't provide.
Commoditization took time, early PC market didn't have the direct model. And the race to the bottom in PCs isn't the fault of the manufacturers. It's an effect of the business model, and customer decisions. If a large segment paid up for better PCs and local support that model would still work, instead they predominantly choose to save a few bucks on the purchase price by buying the cheapest ones with crapware.
It's insane.
Source?
AFAIK they made over $10 billion in revenue on Surface.
MSFT commoditized your business and sucked all the profits out of your eco-system until your net margins were 2%, forcing you to cut R&D, Design, etc, and compete in a brutal price war without much hope of unique differentiating features or value.
Now MSFT is directly competing with you by so lavishly spending on design that they are years away from making money on their Surface line.