Hank, sometimes you ask tough questions.

No, taxes do not go up every year. Should I stop there?
Market value varies from year to year, but not all Counties adjust values on a yearly basis. Some do. Some Counties are on an annual revaluation, some are on a 4-year cycle of revaluation, and some may even be on a 6 year cycle. Those on a 4-year cycle appraise property as of a specific date once every four years. As you can imagine, property values can change dramatically over a 4 year period. Any arguments about value (as in "I had an appraisal done.") must reflect the value as of the revaluation date. In other words, if the value drops two years after the County appraises the property.....tough. You are stuck with the value until the next cycle.
Keep in mind, that market value and taxes are not synonymous. The formula (simplified) is Budget = (Total Assessed Value) x (Levy Rate)

As you can see, if the budget remains the same, and the assessed value goes up, then the levy rate goes down. Perhaps more simply, if all properties were assessed at half of their market value, the levy rate would simply double to raise the same money for the budget. Levy rates are calculated last.....the other two figures are known numbers.

Many misconceptions out there, but the above, while over simplified, is correct.