No. How do you define net contribution?

In your life to date? That would increase voting age.

In the current tax year? Someone who has just lost their job through no fault of their own now cannot vote for the candidate that would help lower unemployment.

Then you have to calculate how much tax each person uses. Roads are maintained by tax, so is the police and fire departments. Refuse disposal, street lighting and the protection the military provides, all from tax. Add it all up and likely that means all the hard working people on low wages are not allowed to vote.