Not necessarily, since I have plugs in all my corners, but wouldn't want to have to stretch wire from an AV amp to those corners.
To the OP, I'm aware of Sony doing a wireless add-on kit (and selling wireless home cinema all-in-ones), and KEF do a wireless transmitter, but don't know if you can buy wireless speakers separately, or if those manufacturer's offerings are brand-specific. Maybe worth googling those two brands with "wireless" and seeing how far you get.