I agree, I just spent an ungodly amount of money on this TV, only to find out it does not support chromecast, and does not work with google home.
Where as all the ingredients are there, you should be able to apply an update, or provide it as an app pretty dang easily.
Come on LG, that is the only negative thing I can say about the TV, and it should be easy enough to implement.
For those of you who are impatient like me there is a work around. Purchase the Harmony companion /home control remote. you can set it up to work on the LG TV fairly easy, and then get google home to sync with it. it's a bit of a process, and you'll want to set up many routines to simplify the commands, but it is doable, and functional.
You can also set the tv up as a wireless monitor, but the lag creates a horrible audio sync issue that makes it impractical for watching media that way.
and you can also purchase a chromecast, but once again where all the ingredients are already there, that seems like a waste of a perfectly good hdmi port, and an unnecessary expense.
I paid enough for the TV, you should throw that in, and the sooner the better please.