Adding to Andy Yan's answer, I would like to bring up another reason: The absence of Google.
Because the China government, driven by an evil party, does not like Google, all Google's services are blocked in China, except for Ads, Maps and Translate (the only 3 availables). Apps using GCM or any other kind of Google service will not function correctly on that part, so Chinese companies pretty much have made their own "chain services" for IPC and push notifications. These services however, does not comply with Google's developing standards, nor do they follow the general rules of UX and memory management. Most of them keep themselves in background by creating extra processes and use those to wake themselves up periodically, taking extra RAM, which dramatically decreases battery life and hurts UX.
Even worse, instead of having one service family exist, big Chinese companies are making their own service families one by one. So Alibaba has an Ali Service, Baidu has a Baidu Service, Tencent has a Tencent Services, and even Xiaomi has a Mi Eco Services. To make things worse, one Chinese app may use multiple services at once. Even if an app is calling a small function from a Chinese service, it may potentially wake up all apps using that service (unless terminated), and can eat up your RAM in a few seconds.
As China is a growing producer, Chinese products are selling abroad, especially South Asia (India) and Africa. By selling phones without GMS, the aforementioned Chinese service families are also spreading abroad, damaging UX to those users. However, situations seems better outside China because most foreigners do not use Chinese daily services like IM (WeChat and QQ) and online shopping (Taobao and Jingdong), and fortunately the services they use (WhatsApp and Amazon) don't utilize the Chinese services. So markets in India and Africa don't get that much "inflated".