My first thought was, "should programmers edit open source for pay," to which I believe the overwhelming answer is yes. It is core to the benefits of free software that those who can't program and want changes or to contribute can pay someone to perform on their behalf.
How is an open source encyclopedia different?
Particularly since, I noticed in the comments a link to this:
The reward board is an informal page where users who want a specific task related to Wikipedia (such as the promotion of an article to featured article status or the editing of an image) can offer a reward to editors willing to take on the task. The execution and details of the transaction are the responsibility of the participating parties, and the reward can be monetary, goods (books, cookies, etc.), barnstars, or tit-for-tat editing (like improving another article).Wikipedia:Reward boardThe answer is, they do.