Why Ethernet just won’t die.

Even if your router doesn't support multi-Gigabit Ethernet, you can buy a 2.5GbE-compatible switch for around £100, enabling client devices to talk to each other at top speed, while maintaining a gigabit connection to the router. This means you can, for example, have a 2GbE connection from your computer to the router, or a 2GbE connection from the router to the NAS - but not both. Environmental interference is a non-issue, and you don't normally need to worry about network congestion, either: while wireless routers have to divide up their bandwidth between any number of clients, every Ethernet connection represents a dedicated full-speed lane. Through the combined cleverness of IP and the Ethernet standards, the router can address and manage clients "through" the switch as if they were directly connected. [Extracted from the article]