The fact that 2Greet switches automatically and provides voice over the WiFi connection means that users can go over their WiFi instead of installing femtocells.
Femtocells provide coverage in places where the signal to the main cells is too weak, like your subscribers homes.
Selling Femtocells to your subscribers is not cost-effective for anyone. The users have to buy them in order to get signal inside their homes and you lose money whenever you close such deal.
Nowadays, everyone has WiFi router at home and most of the users just disable data and use the WiFi network.