The city officials are to blame as far as Im concerned. The taxpayers will lose a ton of money in tax revenue if the team leaves town. They should have calculated how many years the stadium would last and made an educated guess on how much of a fee to add on to ticket prices. Then when they did need a new stadium they should have the money they would need and keep all the tax revenue.
I'd actually consider allowing tax dollars to be used for a stadium, if and only if, the team used its revenue to refund the tax payers. For example, The Vikings won the Superbowl, and generated alot of revenue. If that revenue is sent to each and every tax payer in the city/county or whatever and was given a check or refund for the money spent on the stadium and a portion of the profits.
In other words, make the sports team a public organization, rather than a private organization. And when I mean public - instead of generating revenue for the city/county, it actually generated revenue for the tax payers who chipped in.
We both know this would never happen, and the portion returned to the tax payers would be indeed less than what was spent on the stadium and once the money was taken out of the tax payers pocket, it would never be returned in any fashion what so ever.