system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do big companies/colleges maintain high internet speeds across hundreds of people's devices?

It was a random thought that occurred to me. I've heard about how connecting a ton of active devices to a home network can cause congestion (and slow it down?). I'm a university student and I am always able to have a fast internet connection even when there's hundreds of people in the same building as me using the network.
gpt
Your building has lots and lots of access points all connected to many, many switches. Each switch is likely to be able to handle a Gbit of traffic *on each port*  so for a 24 port switch that's a 24+ GBit back plane. 

Your college also has an industrial level internet connection. And if its a large research institution it likely is a node on Internet2 which is an all fiber network that connects lots of colleges and other institutions. When you data needs to get to one of those institutions, it gets automatically routed over the super fast fiber connection.