It's not the same network. There are three providers in Switzerland. From my own experience the most expensive one (Swisscom, by whom this article is) has much better coverage in the mountaineous areas compared to the other two.
The main differentiation is support.
> The main differentiation is support.
Might be a case of decoy effect in action. Swisscom (the expensive option) gets more customers by introducing a cheaper option with worse support. https://en.wikipedia.org/wiki/Decoy_effect