Also, I tend to refer to the sort of thing I showed as a "satchel". Male soldiers, messengers, hunters and travellers have worn satchels for thousands of years to hold extra junk they may be carrying.
In fact, the word itself is derived from the Old English
sachel, itself a derivation of the Latin
saccellus, a diminutive of
saccus, or bag. As in...it's a small bag.
We sort of went through a period of less-carried for men in the 20th century, and have just returned to how things were before. In the early 20th century, trousers were used to carry a wallet, comb, perhaps a key or two. A few cigarettes in a slim art-deco chrome case if they smoked, and a thin book of matches. That was it. Before that, people carried a tinderbox, a packet of tobacco and pipe if they smoked, often a utility knife of some sort, travelling papers, a good bit of coins, and perhaps some provisions like hardtack or jerky. If they had a revolver or derringer, extra shot, caps, powder, and beeswax or some extra paper cartridges, too.
Now we carry car keys, a wallet with lots more in it than a few banknotes, a cellphone, maybe a PDA or iPod, flash drives, all of that. Realistically, a satchel or messenger bag is returning to our roots of carrying a lot of junk...without saggy, bulky pockets full of junk that look really, really bad for anyone.