A great example of how this can blow up in their face is a recent T-Mobile visual voicemail app. Not only is it slow, buggy & constantly crashing but they had the audacity to place advertisements in it. For some reason, customers didn't like being forced to use their time & metered bandwidth to view shitty ads (the "Click here to upgrade your memory!" sort) while using a service that they had already paid for. If you look at the Play Store, you'll see brazillions of 1-star reviews complaining about this. Fortunately, T-Mo listened & removed the ads. The app is still slow & buggy. I still can't uninstall the Slacker app or remove the Fox News bookmark from the browser but at least I don't have to stare at advertisements while waiting for my voicemail to crash.
Manufacturers & Carriers need to recognize that the value they bring to the table with Android is by providing good hardware, low prices & good service, not crapping up an awesome phone with reminders that Samsung & Verizon are the Best Thing Ever.
Samsung is very keen for you to think of your phone as a Samsung phone, not as an Android phone made by Samsung. So to them it makes sense to reinvent standard components, even if it doesn't make the user experience any better. And Samsung does seem to be managing this, though I don't think any of the other Android OEMs have.
Cyanogen: http://betanews.com/wp-content/uploads/2012/09/cymod2.jpg
Samsung Touchwiz: http://r.phonedog.com/shared/images/2011/8/169026-a-TouchWiz...
Maybe the very bottom barrel discount generic Android device makers don't care about this but you get what you pay for.