China surely has population centers where they can store supplies that will shorten their supply routes.
The biggest issue is, Tibet - for most parts is an arid-cold desert, which means even in winter it snows very less in most places. That means their roads will be open and they move men & material. Cold can be tackled with climate-controlled living areas & bunkers.
This is not on our side, we have high mountains compared to the relatively flat Tibetian plateau on their side. Also, our roads & passes become blocked by snow in winter months, and keeping them open sometimes is just not humanly possible. This poses a great disadvantage to us. To mitigate this, we have built a large number(relative to Chinese) of landing strips & airfields throughout LAC.
What we need are multiple tunnels that can be kept open in winter months than mountain passes which freeze. I believe BRO is working overtime since BJP came into power, but I don't have exact statistics of our progress.