SemanticWiki
would be a key feature in making that idea a reality.
Parsing the plain text articles can only provide very limited data for
answering such questions.
Infoboxes and so forth are very popular on en:wp - Google already uses
{{coord}} like this, but the other infoboxes are a pretty good source
of this sort of parseable data. Note that infoboxes are not entirely
consistent as yet.
That's what I mean by limited: you can only get data that is in
infoboxes. SemanticWiki would allow the parsing of far more data.