If a military would really want to make "Mechas" go usefull, we would have had Veritechs by now
. Maybe the cost and efforts into developing a usefull mecha wheight up for the effect of it...at least at this time, and you have to take the gravity factor of the earth when you want to make giant mechas...too large and they are impossible to move without a huge power boost and that kind of power will be hard to get. A nuclear reactor in the mecha will never be allowed so the only way of powering it up would be a working fusion reactor. Another type of material would be needed, something stronger and lighter than steel or any kind of alu breeds. So for warfare, an agile and strong mecha would be needed. I don't like war so I would rather see them doing some constructing and transporting
