There is nothing wrong in starting with metros and tier-2 cities. Just setting up WiMax in rural area is one thing, providing equipments and training to use the network is the most important thing. So, once the setup is successful in metro and you have good income from those cities, the telco can tie up with NGO and other agencies to spread awareness and provide required training in rural areas. The reason it will all soon come to rural areas is because of booming retail market in india esp. for farm products. Unless the retail biggies setup good supply chain with the rural india it won't be successful...and you would need the accessibility to the rural town/villages to make it happen.