There are consumer 10gbit switches now, though they are on the pricy side at around $400. I bought 3 of them for our datacenter and 2 of them broke within 2 years, so I definitely regret buying consumer grade for our operations but professional gear was ridiculously expensive then. Upgraded to ubiquity now, hopefully it's more reliable, though I guess it's on the prosumer side if you ask your average net admin.
Well, when I say consumer, I mean unmanaged and less than $100 for 4-8 ports. I assumed that when gigabit over UTP was formalized in 1999, I wouldn't have to wait a quarter century to upgrade, but here we are. And to be fair, gigabit still basically does what I need.
I'm guessing it's less than the one or two dozen 60 watt bulbs I used to use to light my house. But yes, I've heard this for a long time - at my work we used twinax or fiber often for top of rack switching and that's one of the reasons I was told. Not sure if twinax is much less power intensive, but I do have a buddy who's using regular old coax in his house (moca or something like that) as a multi-gig backbone (still less than 10G) now and he likes it. Nowadays that I have more money, I would have run fiber alongside the cat 5/6 cable to future proof things, but I'm told terminating fiber is a technical challenge. I guess there's no free or even cheap lunch for 10G yet.
