[_hypx]

Iron is one of the most common elements in the Earth's crust. It is not going to run out.

[jhp123]

Amount in the crust is hardly relevant. After all there are trillions of tons of lithium etc. in the Earth's crust. Transition to a "hydrogen economy" would put unprecedented demand on existing sources. It's not realistic.

[_hypx]

Hydrogen is also one of the most common elements in the Earth's crust. Hence why it will never run out. It is very relevant.