>>510425237
For one you don't have mountains everywhere where you want to build military bases.
For two not all mountains are suitable for deep underground work (has to do with soil types).
For three it is VERY expensive and VERY time consuming.
>how common deep fortifications are in China
Do you? Enlighten us with some sources.
>Mobility is king in expeditionary warfare.
So Russians are retarded for relying heavily on mobility to take ground in their Special Expedition Operation?
I'm starting to think you're a well-poisoning kike who's just here to shitpost.