Let's get back to the sentence that's quoted at the beginning:
"Open source is a development method for software that harnesses the power of distributed peer review and transparency of process. The promise of open source is better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in."
1. This sentence is about "open source development method", not "open source software" (two different classes of objects). Software can be open source (if its licence is open source, i.e. acknowledged as such by the OSI) but not developed using the "open source method" (i.e. if, still quoting the initial sentence, it doesn't "harness the power of distributed peer review and transparency of process").
2. A "promise" is just a promise. Whether it's realised or not is still, to a large part, up to the talent and determination of the developers, or organisations, doing the work on the project.
3. Also, "better", "higher", "more" and "lower" should be defined in the context of which object we're talking about. In this case, this is implicit but I guess the comparison should be with similar software not developed using the open source method, i.e. with not distributed peer review and no transparency of process.
4. Last, I'm sure that both FSF and OSI agree that putting "an end to predatory vendor lock-in" is a good thing. Two bad the FSF doesn't mention it in this text.