The main difference it that I can install a fresh copy of Windows or Linux on my PC and it works, while there is no such thing as "stock Android". It depends on the hardware, so the OEM have all the power.

I got a Nexus S loaded down with crapware I couldn't even use (since it was all in Chinese), but which drained the battery like you wouldn't believe.

Within a couple days, I had removed whatever godawful contrivance was on there when I bought it in favor of CyanogenMod. Truly, the OEM (NB: the OEM here didn't even install the crapware) has all the power.

CyanogenMod is the equivalent of installing a fresh copy.

at the cost of your warranty

What do the Nexus lines of phones come with?

The "Google Experience" version of Android

I think that if the market was fully competetive, everyone was fully informed and both customers and companies made optimal decisions, then most phone wouldn't have bloatware. Otherwise, it would mean that phones with bloatware are actually better than (perhaps slightly more expensive) clean phones. But I just don't think this is the case, bloatware simple doesn't have much real value.

Even in extremely competitive market, there's room for bloatware if many customers don't mind it in exchange for lower pricing. However, what a competitive market WILL ensure is discovery of an 'acceptable level & implementation' of bloatware that 'some' customers will tolerate given the choice of lower pricing vs no bloatware.

Think two versions of Amazon Kindle with and without ads. There's market for both. The problem with carriers is that their monopolistic positions enable them to engage in abusive practices. (like installing bloatware to the point of annoyance, prevent user-removal, and not passing on savings)

I think one big feature of bloatware is differentiation. They want customers to choose phone based on which bloatware it has or doesn't have, because software is cheap. If everyone just wanted to maximize benchmark points or whatever technical spec for a given budget, and it was possible to do straight comparisons, profit margins would decrease. So they make up those extremely hard to compare offers to prevent that. Since customers will presumably try to find a product on the efficient surface, no one wants a product that is inferior in every respect, the approach is to make dimensionality as high as possible.

With offer a you get a fast cpu, a weather app, and free surf between sunday 1pm and sunday 3pm. With offer b you get lots of ram, control your tv app, and cheap calls within our network.