@shainemata's thread
I think the prevailing opinion is that they want to keep the business local. Therefore, by adding incentives, they can ensure that those businesses don't go somewhere else where incentives are offered.
There's a similar issue with most cities having economic development, corporations, or other economic development departments. These entities will give sales tax rebates or some other form of tax incentive to companies to set up shop within the city limits. Sometimes the deal works out and the company is able to collect on the reimbursements. Other times the deal doesn't work out for the company and they forego the incentive as they made more money doing something different than the agreement.
My biggest criticism is that these types of incentives are usually towards companies or people who already have money. If nobody offered incentives, they would still have to choose somewhere to set up the shop. And let's say that a city is poor and doesn't have the resources to give up sales tax, if the company still wants to set up shop, they will without the incentive. Now things are to the point where companies automatically ask for tax incentives just because they know that they can get somebody to budge simply by asking.