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.

When a situation calls for more than Soma, but less than Nerve Stapling, there's Lybrium

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.

A moonsteel armlet set with diamonds

A rare male only Imbrian armor

Armor and accessory set worn by the guards of the Imbrian Royal Palace and the Lunar Temples

The Knights of Imbria are most commonly seen in artwork bearing their famous, or infamous heart shaped escutcheons

A destroyed Kingdom of the Moon, Imbria was lost and it's flotsam of debris rained down on Earth. Among the treasures of shattered Imbria were it's Ancient Swords

Better known as the Ghost Suit

The best example of space designed power armor

Light personal armor worn in the Cosmic Era, the intermediate between flak jackets and ballistic plate and full powered combat armor

The basics of magnetic weaponry in the Cosmic Era

Not all magic items are for humans. Rewrite of my original and premiere submission, Horse Brass

Based off of the Rubik's Cube, the Emote Cube is a banned piece of arcanotechnology

The Sperry-Colt 7.5 cm automatic rifle, standard weapon of battlemechs for the Atlantic Federation