That sounds a bit hyperbolic. I think you're overreacting. The difference between this and long-polling in terms of hardware required is pretty minimal. I run a web stats service that has to deal with similar kinds of data -- millions of sites "pinging" it with a new page view to record constantly -- with one crappy server. Nest doesn't even have to record anything in response to those pings, unlike my server, just compare to some in-memory table of which devices have commands waiting for them, so most connections can be immediately disposed of.

Given the setup, network and power requirements Nest operates under, this may well be the most efficient way it can be done. Or maybe it does do some kind of long-polling and the descriptions online are inaccurate. Either way, I doubt there's anything "absurdly wasteful" going on here. Poll vs push isn't melting polar ice caps.