In the past, import restrictions did not cause serious social hardships when most manufactured goods were imported, because imports of such luxury goods as automobiles could be restricted in times of balance of payments stringency, and liberalized when export income permitted. With industrial progress, however, balance of payments difficulties have necessitated the restriction of imports of industrial inputs rather than of final goods and this has led to unemployment. 'Stop and go' policies have thus become very costly. Excessively protected infant industries often failed to grow up, though some have become competitive exporters. Where foreign investors were attracted by high levels of protection that enabled them to make monopoly profits, high volumes of remittances added to balance of payments problems.