The reasons that mecha are not reliable as weapons of war are manifold, but the world changed more than many people expected and the way wars are fought have changed greatly since the middle of the Petroleum Era.
The most common form of body armor in the Cosmic Era, also the cheapest
30 pistols, rifles, and assault weapons
Protection in the Cosmic Era
The biggest reason that Amerikka Command survives to plague the Atlantic Federation, the only reason the ACPS hasn't destroyed the Python Pirate Syndicate, is their mastery and sharing of shroud technology.
A foundation 'Secret' of the Cosmic Era
The commericaly available firearms of the Cosmic Era
Those sissy boys in the army, they gotta have their 'bots and guns, shiny vehicles and iron suits. Me, I don't need none of that. I've got everything I need on me.
Cagle, Claremont Class Biomod Mercenary
When a situation calls for more than Soma, but less than Nerve Stapling, there's Lybrium
A look at slums and shanty towns in the Cosmic Era
Gotta have dat juice!
Golgotha, Shadowrunner and notorious Juicer
Not all armor is created the same, some is made from sterner stuff, others, not so much.
They're doing it, they're really doing it
One of the largest objects in Low Earth Orbit
Meta Level submission about the nature of conflict in the Cosmic Era.
Better known as the Ghost Suit
The best example of space designed power armor
An uncommon, but visually dramatic body modification in the Cosmic era
A common light mech of the Atlantic Federation
Light personal armor worn in the Cosmic Era, the intermediate between flak jackets and ballistic plate and full powered combat armor
One day a year is the Day of Turning where those on the bottom of the heap for the rest of the year get to live like Kings. Privates question Generals, the people get a say in running things and there is great merriment and gift giving.