Question: I often see the number of votes/answers/general interest in questions on Meta Stack Overflow to be much higher in number. There isn't much doubt that the questions here are a lot more interesting and prone to debate.

But shouldn't people spend time giving answers there rather than here?

I mean, that is what is more productive, right?

Answer: 
I don't share your view that there is more interest for questions here than on the main site. What I do see is this:

* There are more 'subject experts' here on MSO than on SO for specific tags. The population on SO is mostly interested in their own tags while people here are broader since it concerns the entire site, which everyone knows.
* There are far fewer posts on MSO. Thus they got more attention per question than questions on the main site. Also the 'hot meta questions' box will draw even more attention.
* Concerning the votes: opinions draw more votes in general since people want to have their opinion reflected. A question on SO itself is mostly judged on the correctness and has less 'emotional' way of voting.
There are 10million+ questions on SO and only 15thousand+ on meta.SO.

There are about 400 bounties at any give time on SO. Meta.SO doesn't have bounties but does have the "Hot meta posts" which features about 4 questions at any one time from meta.SO on meta.SO and SO. 

So as you can see, much easier for people to find one/two/three really popular meta.SO posts, since it's a much more narrow area. Whereas SO has hundreds of different areas and most people only frequent a few areas. 

So meta.SO is the only bar in town, but SO has many work places.