Some comments have already touched on this, but it is important to realize just how much electricity we are talking about. The tl;dr is that replacing US wheat production alone would use five times the current total US electricity consumption. And that's for wheat, occupying about 10% of US cropland.

See p. 12 of the Supporting Information and you'll find the following: 2026647 kg wheat grown using 798417 MWh electricity means an electricity consumption of 0.4 MWh/kg wheat. In the US, the annual wheat harvest is 150-200 kg/capita/yr, which in this hypothetical system would use more than 60 MWh electricity/capita/yr.

For comparison, the US annually uses around 13 MWh electricity/capita.

That is, this hypothetical wheat production in the US would use about five times the _total_ present day electricity use.

Soybeans and maize together occupy more than three times the wheat area in the US, so that (very roughly speaking) adds another annual electricity consumption of ~200 MWh/capita. With just these three major crops, the US would have to increase its total electricity consumption about 20-fold.