Lower priced drugs have lower margins, hence lower incentive to invest / modernize production to meet the increasing FDA regulations. Many drug co’s are making decisions to discontinue manufacturing based on the profitability. some avoid / defer investments until reality sets in.
can you show cases where a more expensive drug is benefiting from the short supply of a generic?
Here's one article I found online that mentions it:
http://www.nytimes.com/2011/08/07/opinion/sunday/ezekiel-emanuel-cancer-patients.html