(All italics and bold are links to sources)
Against China, this has always been the case. No one has ever expected such a large deployment against them - even the Chinese were caught unawares by the scale the deployment grew to. Hell, they lacked
even basic winter clothing whereas we didn't.
Here, in fact, is a Chinese source (South China Morning Post) in which the PLA indirectly admits to their troops not having enough cold weather gear. And in regards to surplus, the Army didn't need to purchase surplus until a few months into the stand-off, ordering them as late as October of 2020 when the stand-off started in March, pointing to an already existing stock.
Saying that the Army should have had enough surplus for 200k+ troops ready is like saying the British should have had thousands of Spitfires in service before the war with Germany. You cite America's wars, but during both Gulf Wars the US Army didn't have enough body armour ready for all its frontline and rear deployed troops.
Source 1, Source 2, Even the British were short of body armor, Source 3. And the reason the Americans had so much surplus winter clothing is because they had huge deployments in the Hindu Kush mountains.
Furthermore, the winter clothing bought by the IA in 2020 was mostly to restock exhausted supplies, with the majority of the stocked winter clothes having already been dispensed. Even then, the IA only ordered
11,000 despite having anywhere between 150k-200k troops deployed and possibly 60k+ on the frontlines. In the middle of the hostilities, the IAF and Indian Army set up an amazingly efficient logistics chain (
Source 1, Source 2). After the order of 11k sets of winter clothing, there has been no repeat order. The most likely scenario is that the 11k sets bought from US Army stock are part of the contingency as there has been no images of Indian soldiers wearing US stuff on the front lines. Yes there are plenty of photos of US clothing in rear camps or officers wearing them, but if you look at images of the actual front line, there are none.
I understand where you are coming from, but as there are those in this forum who are amazingly blind to the IA's failures, you are blind to the IA's successes, looking at half the information and coming to incorrectly drawn conclusions.