It's my understanding that many are doing it for the money and other benefits. The benefits are the stuff of dreams for many who join. Medical, dental, education, housing, pension, genuine advancement prospects, coupled with a steady job that won't vanish in a weekend. These are big draws, especially to a person whose other option is a zero hours contract at a chain store. I've been a reservist (non-US) for almost 20 years; I certainly am not in it for anything involving serving my country, although of course everyone has their own motivations.