This article (and most of this discussion) completely misses the elephant in the room.

The reason food crops are less nutritious has nothing to do with their soil and everything to do with their food: CO2.

It's widely held and widely accepted that if you give plants a higher concentration of CO2, they will grow faster. They will take up more space in less time.

We also know that the CO2 levels on Earth have been skyrocketing.

Thanks to CO2, these plants now spend substantially less time in the field before they get harvested, so it stands to reason they'd spend less time taking up minerals and vitamins, or forming them themselves.