It has evolved of cause. One of the sources you referred to, the OSI, has a clear agenda to define the term open source software according to their own definition. They are advocating that we use the term in the more narrow sense as you described, rather than the more original broad sense.

The Wikipedia article basically just cites OSIs definition. If you dig into the talk page on Wikipedia it is clearly a disbuted definition that is currently written.

While I absolutely am a proponent of free, libre or open source software, no matter what we call it, the narrow definition OSI suggests of open source software is still not how most people understand the term.

Narrowing the term open source software the way OSI proposes increases the confusion, it doesn’t help.