Mdirash Rabba Breishit, Toldot 64:2 – Chazal seem to recognize the difference between high prices and a bona fide shortage. A shortage happens only when buying and/or selling at the market price is forbidden by government. If prices are mandated by government to be lower than the market price, a shortage will develop when more buyers than sellers are willing to exchange. Some buyers will not find what they want. At the market price, the amount of buyers and sellers equal out.
The Midrash here is discussing the famine that Yitzchak tried to escape from. God told him to stay in Israel and not to go down to Egypt like his father:
Is it not taught that one may not leave the land [of Israel] unless two se’ahs of wheat are being sold for a selah? Rebbi Shimon says when does this apply? When there is no wheat to by. But if there is wheat available, even one se’ah for a selah (meaning twice the price as above) one may not leave the land. Since Elimelech left the land he was punished, in that he and his sons died.
If food is very expensive in Israel, it isn’t sufficient reason to leave. But if there is a shortage and you can’t buy what you’re looking for, then you can leave. Nafka mina bewteen high cost of living and real shortage of goods due to economic intervention. Without government, there are no shortages because price always finds market level.
The Jewish Libertarian 
Are you saying that the shortage in Elimelech’s time was due to government intervention? Doesn’t it say ij the verse, there was a famine? Further, didn’t he live in the government-free days of the Judges? (no king in israel.)
No the midrash is saying davka there was no shortage, only high food prices. If there was a government-induced shortage Elimelech would not have been punished for leaving, ostensibly. The fact hat he was punished through the death of his family proves that there was no shortage, only high food prices.