Suppose that a city mayor proposes to pay for the acquisition and construction of public parks by implementing a 7-year local sales tax. Someone argues that the financing mechanism should instead be something that is spread out over more time, noting that a person who moves here 8 years from now would get to enjoy the parks but under the current proposal wouldn't pay for them. Similarly, this individual argues that those who live in the community now pay for it, but if they move, they won't benefit at all from it after a few years. The mayor argues that those who move out of this area will in fact benefit from the parks beyond their personal use and that those who move to this area after the 7-year period will implicitly pay for the access to the parks. What does the mayor mean?