On the other hand, people might upgrade their hardware more often if they could be assured their new hardware wouldn't come with Microsoft's latest abomination and a shit-ton of bloatware.
I highly doubt this. Most consumers still call their computer case the "CPU" and buy new computers when they don't have to because they don't realize Windows and their computer are different things. Basically, the average person looks at their computer like they would an advanced VCR.
The sad fact is, most people go out and buy new computers precisely because it has the newest version of Microsoft's abomination and all that bloatware which are marketed as features on the box and by the Best Buy droids. Computer manufactures know this, love it, and bank on it. It's how companies like Intel can get away with requiring a new goddamned socket every year (or less) and not have people storming their castle with pitchforks and torches. My parents don't care. Dell don't care either, because they're selling whole systems and not parts. Likewise, every time Microsoft come out with a new version of Windows, computer makers start seeing dollarsigns.