What's the point in a fast Internet connection when Windows Update doesn't use it?

In the last ten years, I have seen WU downloading updates at what was the full speed of my Internet connection (~70mbit/sec). Now I'm on ~500mbit/sec, I haven't once seen it do it, and lots of computers have been connected to my Internet connection via ethernet or wifi. Right now I've got a computer connected to the same switch as my PC is and WU is doing a super-light-speed fast ~12mbit/sec at best. Yes, it has a 1.0Gbps network link, and sure enough if I do a Google speed test, it's hitting >460mbit/sec. Often when WU is claiming that it's downloading, it isn't, and is instead caning the CPU/disk, and often when it says it's installing an update it's actually downloading it. On Linux, if I run an update check, it will happily go up to ~500mbit/sec until it's finished and then get the hell on with the update installs.