The article mentions other benefits, such as many Italian farmers lost their harvest in the drought of 2024, while many traditional grains fared better in the dry climate and could be harvested.
The yield of this wheat is 1.5 (Miracle Wheat) vs 5.8 (Standard) tonnes/hectare. That's about 25%. Since wheat can easily be stored for many years, you would have to have droughts in 3/4 of years before you break even due to drought resistance. In the meantime farmers can barely break even financially growing this stuff.
*HOWEVER* Miracle Wheat is very very susceptible to lodging (falling over and dying in the rain). So in years where there isn't a drought you would sometimes lose almost 100% of the crop. So even if there were droughts 3/4 of the time, you would still never break even.