I'm confused<p><i>It’s simple – here’s how it works:</i>
<i>Say a community is built in Year 1.</i>
<i>The community’s streets need to be rebuilt every 30 years.</i>
<i>In Year 30 a new, identical community is built. Now twice the amount of taxes are coming, and so for time being the property owners only need to pay half the amount.</i>
<i>And 30 years later, in Year 60, two new communities are built; as long as the number of properties and property taxes are doubling every 30 years, they can continue to pay half the amount.</i><p>Year 1, one community (community A), over the next 30 years is going to pay for 1 community's worth of roads (call it a 30 year loan given on day 1, let's say 1M dollars). So, the cost for community A is 1M dollars for 30 community-years of roads.<p>Year 30, we add a new community B to the mix. This community needs its own roads, so it needs a loan for 1M dollars it will pay off over the next 30 years. However, community A's roads have worn out. Community A just finished paying off their first loan, so they'll need a new one.<p>At year 60, we have paid 3M dollars, and gotten 90 "community-years" of roads out of it. This is no different than the equivalent end of the first year with one community, one loan, and 30 "community-years" of roads.<p>What am i missing from this example?