I think the economical point of view is still missing in this discussion. Consider this: Even in the second half of 19th century during the American Civil War it was somtimes very hard to equip an army with a uniform or adequate weapon. This was happing in industrialized world, when most of the hard metal-working manual labour was replaced by heavy machinery powerd by giant steam engines. Steel was produced in milions of tons per year. (According to: http://en.wikipedia.org/wiki/History_of_the_steel_industry_(1850–1970) ). Textile-industry was even more progressive (According to Wealth and Poverty of Nations - David Landes). And still, there was lack of some esential eqiupment. It's estimated that around 100 AD the anual production of iron was 84 000 t. (http://en.wikipedia.org/wiki/History_of_ferrous_metallurgy#cite_note-30). That's just 0.84 kg of metal for each inhabitant of Roman Empire. Since less then a half of this production was used in military, that's just about 0,4 kg. Just enough to make a spear - and nothing else. Now, the price of such spear would be astronomical whan adding the work of a blacksmith who used just his own hands. I admitt the calculation is very simplified but we should consider the lack of resources in that point in history.