[shibapuppie]

How?

When canbus is already two wires, and by definition, is a bus, so you can just keep stringing those two wires to any module you need. I know Ethernet BUSes exist, but what advantage would those have to canbus then? They're both two-wire buses.

[BenjiWiebe]

Canbus is much slower than single-pair Ethernet. So you can get more data (more modules connected) over a single pair of wires if you switch to Ethernet.