The Switchback is a 631 front triangle and 525 stays, so that’s more Reynolds steel than in an 853 Soul!
However, my understanding of the Cotic Fm is that it’s basically their own brand version of 631, thus less expensive but equally strong. And they’ve only ever used 4130 stays because they’re strong enough. The BFe is a very clever design for getting maximum strength for minimum weight and cost. They probably do more direct sales than the other companies too, so tighter margins through their few dealers.
Having ridden an alloy hardtail for coming round to two years, I’m struggling to convince myself of the extra weight and cost for steel (ignoring very long term durability).
The numbers do vary a fair bit – it doesn’t take much change in BB height to make a bike feel quite different to another. Likewise chainstay lengths.