The internet being bad is done on purpose. They don't have to make it shit with the traffic analysis, since internal traffic has traffic analysis too. They do it to keep china's internet an internal, more easily controllable intranet.

I've been fortunate enough to have access to non-GFWed bandwidth to play with on several occasions, and my experience would seem to suggest this is accurate. I can easily sustain 60mbps to the US when not subject to the GFW, but when using normal non-exempt bandwidth from the same (domestic) provider, could only sustain 5-10mbps. China's network architecture in Tier-1 cities is largely fine, and it's really the GFW that throws a wrench in things internationally.

Data localisation regulations are certainly one reason for foreign companies to set up local infra, but IMHO the real reason is that it's the only way to provide an even remotely tolerable user experience to users in mainland China. Aliyun is basically AWS for China and is very easy to get up and running, and getting an ICP license wasn't nearly as hard as everyone makes it out to be (got one in ~2 weeks from application).

NOT GFW, just concerning Apple's money. Chinese have downloaded so much HD video crossing the border through the GFW,but the speed is not so slow as Xcode downloading.

A checksum can only tell you if the file is identical to another. Even if it did - you downloaded the file from untrusted location for a reason - you don't have access to original source.

Checksums are useless if you don't have access to an alternative source.