This is because, the wiki article should have a {{Coord}} template to represent itself as a georaphic object. |
As amritkarma pointed out correctly you have to edit Wikipedia to see coordinates at the article. WIWOSM is a tool for highlighting certain objects in OSM which are connected by a wikipedia link.
As far as I know only the german Wikipedia has embedded this functionality:
To check if entries not available in WP:DE work, you have to have a try directly on the toolserver: example Bronze and Brass Museum |
You’re asking why Wikipedia doesn’t have a link to OSM, correct ? Did you consider sending your question to Wikipedia ? IMHO they should add a link on their pages, isn’t it ? They're free to do so or even do it yourself. |