Needs a lot more arguments to tie that to a rising iron deficiency, or any rising deficiency.

There have been many changes in the consumption pattern in the last century.

Many fruits & vegetables where not available year round, so even if they have less mirconutrients, orange, bananas, strawberries, etc. used to not be consumed as much as now.

There's also been a huge drop in the consumption of organ meats, which contain much more vitamin and minerals then most vegetables (with the exception of vitamin c).