The tax monies collected for the districts go to pay for schools, roads, law enforcement, fire protection, and other services that the taxpayers demand and desire from local government. When additional taxes are voted by the people, an individual's property tax bill will increase. Also, when Market Value increases, naturally, so does the Assessed Value. The Assessor has not created the value.
People make value by their transactions in the marketplace.
The Assessor simply has the legal and moral responsibility to study those transactions and appraise your property accordingly.