Sham disability is an integral part of the US welfare system, because it's politically expedient. It allows the government to pay poor people just enough to avoid a violent revolution, while sidestepping the issue of the "deserving poor". It also conveniently conceals the real rate of unemployment - you can pretend that your unemployment rate is 4.2% if you've recategorised most of your long-term unemployed citizens as disabled. The claimants aren't cheating the system, they're using it as it was designed to be used.

Britain did much the same thing after the decline of heavy industry. The number of disability benefit claimants trebled in 20 years, concentrated almost entirely in towns that used to have a mine, a steel mill or a shipyard. In some parts of the UK, over 20% of the working-age population are claiming disability benefits. Staff at welfare offices were effectively coaching people on how to claim disability benefits, because it helped them meet their performance targets.