That's certainly true, i quite agree with you, but if your able to find a sack that sits well on your shoulders, has sufficient capacity and facilities for your needs, then buy it, and if its a bit out of your budget, safe for it.
Years ago, i was in the same predicament, which sack to go for.
I eventually bought a Dart 45 Berghaus, it certainly was not the cheapest option if i can remember, but it certainly felt extremely comfortable on my shoulders, and i really liked the cordura material it was made from.
All this was such a long time ago, i have forgotten when i bought it, certainly over thirty years ago, probably in Brecon.
After well over a dozen or so challenge walks, especially that final ill fated LDWA 100 attempt, the sack is still used to this day, a bit faded, but almost as good as new.
It was a wise purchase, but i can vividly remember it certainly was not the cheaper option in the large number of sacks then available.