I'd just get wireless powered speakers if I really wanted wireless setup.
Standard Bluetooth or If you keep your eyes open, every now and then a brand will come out with a WiFi network speaker... Someday we will have a replacement for chromecast audio.
There are a few decent options that have been around for a while. Manufacturers like Libratone, Audio Pro and Bluesound. Anything with a built in battery extends the use cases.
I'd just get wireless powered speakers if I really wanted wireless setup.
Standard Bluetooth or If you keep your eyes open, every now and then a brand will come out with a WiFi network speaker... Someday we will have a replacement for chromecast audio.