Why are these drugs underserved though? If, as another commenter suggested, the core reason for the shortages is because the government is such a large purchase

Why are these drugs underserved though? If, as another commenter suggested, the core reason for the shortages is because the government is such a large purchaser and they're keeping prices too low to encourage investment in new supply, wouldn't it make more sense to just pay a bit more to create some oversupply to cope with shocks to the system and long-term growth?