Upon arrival in their host country, the first generation of political refugees has one goal: going back home when things settle down. They get jobs, they create communities, they have children but because their objective is to go back they don't make long term comitments like buying property or long term financial investments. When the children reach adult age they are still living in the host country, but they have grown up in a culture of transcience: never taking root in the 'temporary' host country and not belonging to the 'home' country they have never seen. The first generation born in host countries is often lost, with no identity.
The analogy is a little strong, but joining a team, a project or a company is similar: you know you will leave one day and it's tempting to focus on solving only the immediate problems, to ignore those that will only hapen way down the line. The problem of course is that you never know how long you'll be there - or when those 'long term' problems will show up.
The best use of your time is to spend it on systems that will outlast your presence in the company - because bulding lasting systems wil benefit everyone, whatever their plans for the future.