[softfalcon]

You are correct in that steel is harder and stiffer than titanium. Steel is also more re-usable, smelt-able than titanium.

However, when it comes to fatigue (which I assume, you are referring to fracture strain) titanium has a significant edge. The fracture strain for steel is roughly 15%, but for titanium alloys, it often reaches and exceeds 50%.

I don't say this to contradict you, but to point out that as with most things in life, "it depends".

Source: https://www.ulbrich.com/blog/titanium-versus-steel-a-battle-....

[Gibbon1]

A better argument for steel is it requires 5-10 kwhr/kg to produce vs 60kwhr/kg for aluminum and 250kwhr/kg for titanium. So for the same energy you get 6 times more steel than aluminum and 25 times more than titanium. Which seems to say when the properties of steel are acceptable it's the cheaper option.

https://solar.lowtechmagazine.com/2009/06/how-much-energy-do...