report on wheat market outlook from Jan 2021 is interesting to peruse. there's certainly no one simple answer to why the price rose, but it does indicate higher consumption and lower yield overall in the world (higher yield in Russia but lower in China and Argentina) played a role as well as US wheat planting acreage that had been trending down in recent years. and that rising price of corn meant wheat stocks were used as substitute in feed.

https://www.ers.usda.gov/webdocs/outlooks/100227/whs-21a.pdf...