I don't know who originated the bag, might well be that they got from somewhere around Fennoscandia. The arctic and Antarctic explorers had bags from the start, at least the Norwegians did. Would be interesting to know where the bag idea started.And I think we got the sleeping bag also from Scandinavia.
The army belts, is now used to form what is known as a battle belt, the police call it a duty belt. The inner belt is used to keep your trousers up and is generally the soft velcro side the more ridge side (hook) is the duty or battle side to hold your pouches and equipment. so you can easy detach your pouches as necessary or if you are sitting done but put it quickly on if needed.The velcro sheets could be perhaps sewn together on the teeth side and like this it would become more secure.
I have seen police and army belts with velcro connected inner and outer belt. I think that's invented to hold pouches in place but probably could be used also for a saw blade?
Should that work, we would have found a ready to use plug and play solution that can be bought in a shop, instead of a sewing project.
Perhaps the stuff already exists and I just need to put it together?
We have a a number of Hultafors Outdoor Knives with Firesteels
You can see more details here in this thread OUTDOOR KNIVES
The price is £27 and you can pay via the paypal button below.