Replacing a standard double socket with a new one with double USB ports on it as well takes around 2 mins to do and costs very little. I know because I've done a few in my house.
So the solution to the socket problem in the rooms is incredibly cheap, quick and simple and doesn't require full room renovations to achieve.
But there is no way to charge an up-charge (no pun intended) for the use of the USB socket for charging purposes. Towers will see it as expenditure that does not increase profits.