Microsoft does work at eliminating this kind of thing. They clearly just missed this one.

Microsoft's main source of control over OEMs is the logo program. All laptops that want to get the "Designed for Windows" sticker (logo) have to pass a minimum bar set by Microsoft, which includes things like "must boot within X seconds" or "must sleep within Y seconds", "must output the correct audio frequencies", etc. My guess is none of the logo tests invoke the accelerometer which is why this got missed.

The logo program is great in theory, but in practice it doesn't work too well since consumers don't care about the sticker. Therefore, if Microsoft makes the requirements too high, OEMs will simply stop trying and just sell their laptops without a sticker.

It's hard to imagine another policy without making it excessively difficult for vendors to add new features. For example, a button on a laptop that changes Wifi configuration might need a similar driver program.

Hardware vendors are generally expected supply their own drivers for all but the most common built-in devices. This can include user-mode applications. The driver certification process has greatly improved the quality of 3rd party kernel drivers. In my experience BSODs are really rare these days.

But obviously there can still be quality-of-implementation issues. This sounds like a question of "is this really a good use of RAM from the users' cost/benefit perspective?"

Disclosure: I'm new at Microsoft but my role has basically nothing to do with this stuff. Just my personal opinion as a long time developer and industry-watcher.

What you already know, but need to be reminded, is that there is not one, uniform "Microsoft", who has the power to allow or disallow something. Even in the highest levels of the corporate hierarchy, it takes a great deal of effort to influence the direction of the ship (never mind intentional steering). In the case of OEM shovelware, there were quite a few people who worked very hard to get rid of it. However, Dell alone has substantial influence over this decision through their sheer volume of sales of Windows. When you consider existing contracts, OEM motivations, and internal politics, it's no longer that incredible that this preloaded nonsense persists. What's incredible is that the concerted effort to regain control of the ship doesn't seem to be having much effect.

The anti-trust rulings in the 90s prevents Microsoft from restricting OEMs on the crapware they install on computers.

Oh trust me, the end user of experience of Windows 8 is not something that can be significantly more damaged by OEMs