[rvnx]

The main point of answering to StackOverflow questions is to earn points, points that you can show on your CV :)

"Top StackOverflow expert on XX", so the incentive is still there.

One solution to spam could be to keep the voting system, but not publicly reward users with points (like on HN).

[xwolfi]

Have you seen people do that ? Would make me terrified to hire the dude "will he be paid to post answers to other companies' employees?" :D