Open Educational Resources: What are the pitfalls?

The use of open educational resources (OERs) is undoubtedly more beneficial than harmful for us all,  but for a moment I'll play devil's advocate and examine the pitfalls. Recently, McHenry County College announced it will move to using OERs and away from textbooks. While college students at MCC are likely breathing a sigh of relief, some of their faculty may not be pleased with this recent decision.

While obtaining my undergraduate degree, I took a speech and hearing disorder course taught by an expert in the field. We were required to purchase a textbook for about $70, which wasn't available used, and just happened to be written by our professor. Given that our lecture hall held about 150 students in just one of his classes, the book sale seemed like quite a racket. However, the book was very informative, well written, and our professor assured us it was one of the best available on the topic.

While the ethics of requiring students to purchase your textbook are debatable, limiting teacher choice by only using OERs is concerning. If my alma mater moved to using only OERs, should my professor have to give the materials he's worked on away for free? How difficult is it to find OERs on special topics? You'd be hard-pressed to find a broke college student who is sympathetic of a textbook company, but any losses they have in sales will likely mean cutting sales a production jobs.

Overall, I feel the benefits of using OERs outweigh the pitfalls, but it is important to consider these potential issues. What can be done to alleviate these possible problems?