'Ubuntu Friendly' Hardware Certification Program Maturing

This is definitely the case. I work at Canonical and previously worked on the Hardware Certification team (who produces the list of hardware on http://www.ubuntu.com/certification/ and is working with the community on the Ubuntu Friendly program). The number one issue we saw was exactly this. We'd get a system, test it and enable or certify it, and then the components would change during production. Suddenly people were getting systems that didn't work properly.

It's not always the OEM's fault -- sometimes the ODM would change parts without properly notification. (After all, if they can save a half a cent per device and it still works just fine under Windows, that's just money in their pockets.)

We're working on it. It's gotten better in the past year or two with the major OEMs and we're continuing to improve our relationships with them and the ODMs that build the hardware for them. It's a process of education, driver improvement, and QA that goes on largely out of sight of anyone not actively involved in the process, but it is happening. The good news is that this helps everyone, as the OEMs and ODMs are starting to think about this sort of issue throughout the design and production process rather than as just an afterthought.

Edit: Whoops, meant this to be a reply to joe_the_user

However, what I have read is that to leverage chip prices and availability, manufacturers these days will change the underlying chip sets and configuration of "models" without changing the model # or appearance. The manufacturer has some incentive to keep their official compatibility with Microsoft but you may find that Linux compatibility changes. Those with more hardware knowledge can correct me if I'm wrong.

Off-topic, the problem I've had with laptops lately isn't lack of Linux compatibility but simply that the hardware is total crap on quality and ergonomic side.