That is desirable because we need a good percentage of people to stay put and be pillars of society so to speak. Nomads don't invest in their communities, they aren't going to be there long term. So lower taxes for long timers is a good thing. Long timers pay back in other ways, such as participating in local government, schools, charity work, improving their properties, building social networks, and committing less crime. We also need a good percentage of Nomads too, to keep the economy and work force capacity flexible. I'm currently a member of the Nomad class but do not mind lower taxes for long timers.