Core spun canvas packs

[deeringgoodtime]

I am new to hiking and I am about to buy a new pack. I am wondering why the big Australian backpack brands (Mont, OP, WE) all use core spun canvas in their flagship backpacks, but no American brands use this material? If core spun canvas was the best or most durable material, why isn't anyone else using it? 'Rugged' American packs (Mystery Ranch, Hill People Gear etc.) seem to favour 500d Cordura. From what I have read online, it seems that 500d Cordura has better abrasion resistance and tear strength than core spun canvas, but core spun canvas has better water and UV resistance. However, I can't find any definitive sources or tests that show this. Does anyone know how the abrasion resistance of CS canvas compares to Cordura and how water resistant CS canvas is? (waterhead ratings). Thanks!

[Aardvark]

Cordura is a synthetic material (liken it to plastic) The thread is waterproof but when woven as a fabric, water will go between threads unless it has a laminated coating. The thread is definitely harder wearing but the laminated coating will eventually fail due to folding, creasing, abrasion, age (therefore UV degrading) etc. It isn't impossible to renew the coating to some degree but it is difficult and messy and not very cost effective.
Core spun canvas is a cotton based fabric but can have a degree of synthetic thread woven into it for strength. Being cotton based it is able to absorb moisture as cotton (natural) is porous by nature. This allows it to absorb a waterproofing substance which makes the cotton swell and close gaps between threads. This can be done repeatedly through the life of the fabric.
A waterhead rating is determined by holding the fabric against a tube of water and determining how much water(measured by the length of the tube) it takes before moisture seeps through the fabric. It indicates the pressure needed to get the moisture through the fabric. You can kneel on a sheet of fabric (such as a tent floor) which puts pressure on it at one given point and depending on the waterhead rating, moisture might get through.

[Aardvark]

500d Cordura as opposed to 1000d Cordura. 1000d will be a stronger and likely more durable thread ('d' is for denier - for intents and purposes that means thickness). 500d Cordura will be thinner and lighter.
I wouldn't concern yourself too much about waterhead ratings on fabric used to make packs. It is far more relevant with regards to rain jackets and tent materials. It obviously is used as a marketing ploy more than anything. It does at the same time serve to confuse the buyer.
In particularly wet environs you are likely to employ waterproof stuff sacks within your pack. Moisture that comes in via the outer pack fabric is never really torrential (its just seepage).

The American market is many times bigger than the AUS/NZ one. The majority of people seem to be focused on how lightweight things are. The market is therefore going to lean that way and logically choose synthetic materials. The thinner the better. However the parts of a pack that cop the most wear will often have a heavier denier fabric used eg 1000d.
In my opinion the AUS/NZ buyer will be more likely to choose the pack that lasts longer and that is often the canvas option. Mostly because its easier to repair from abrasion and waterproofing. I'll bet most often the frequent AUS/NZ bushwalker will inevitably have a synthetic option in their arsenal because its lighter.
Lightweight is seductive. I'll bet those that have a canvas pack and a synthetic one, will find as time goes by their using the canvas one less and less.
These are of course, just generalities. Everybody is different and their usage varies. Whats good for one will be different to others.