Unless you only work with other software developers (or gamers I guess) who are latency sensitive like us, most of the people you speak with over VoIP are unlikely to have a Ethernet connection.
Last time I worked full-time in an office, some people didn't even know you could connect to the internet/router via a cable instead of wireless...
If you're talking with them over VoIP, my hunch is that money isn't the problem here (30m ethernet cables cost like ~$15-30), but rather being able to pull a cable through the house/apartment without making it look like an eyesore or even being in the way.
Unless you only work with other software developers (or gamers I guess) who are latency sensitive like us, most of the people you speak with over VoIP are unlikely to have a Ethernet connection.
Last time I worked full-time in an office, some people didn't even know you could connect to the internet/router via a cable instead of wireless...