The following is based on a discussion with my Rov when the price of wheat rose almost doubled in 2006 between April and October.
“famine” is defined as when the cost of wheat rises more than 50%. In the gemara’s times, the price of wheat was fixed so such a price rise is an indication of significant shortage. In our time and our place (both USA and E”Y) the price of wheat is not fixed and of course the value of our currency is not fixed so the concept of such a rise doesn’t exist.
Furthermore, I am pretty sure he said the restriction does not apply to “onaah” rights as outlined in the kesubah.
Finally, in our time B”H there is no shortage. It isnt like there isn’t wheat. Wheat can be purchased. The prices of wheat are manipulated. For example, Russia signs a treaty with the USA and our wheat is cheaper that Argentinian wheat so Russia buys from the USA and the USA prices go up. There is no shortage – the USA consumer just pays more and the USA companies sell the USA Argentian wheat.