Nutrition

Heart disease isn’t a death sentence?

It is. The sentence is saying that lower nutrient intakes moderately change an individuals risk factor for disease. The "not a death sentence" clause is referring to the inadequacy, not the outcomes. Not everyone who consumes inadequate nutrients will develop a disease from that condition, it's a change in risk factors.

Would not having a diet more rich in bioavailable iron avoid the deficiency even in these scenarios?

Not in this instance. As stated later in the text, the digestive system has an upper limit on how much iron it can absorb. Pushing more iron into that system doesn't necessarily result in improved iron intake.

The top soil crisis never even factors into their 2500 word blog. Surely soil, and fertilizer are factors that are likely to change in the near future and to say they won’t have a impact on nutrient density is bold.

Again, as stated, fertilizer applications have plateaued since the 90s. What I'm saying is that, due to the plateauing of input use growth in developed agricultural regions, we shouldn't see an increase in dilution from those sources since conditions crops are being grown under have been consistent for around 3 decades. There's no reason to expect a sudden surge in fertilizer use in developed nations, thus no more dilution from added fertilizer use should be expected.