There are different kinds of operators in a particular region/country. Few operators have infrastructure and few operators just having agreement to share the infrastructure. From user perspective, his phone should have support of LTE, 3G and 2G support what I know till now. It means if can use 2G for voice and LTE for data. It depends on user interest.
I think this is very initial stage for all the operator w.r.t LTE deployments. As of now, for an operator who is loosing traffic at legacy network (results less income) but due to high operational cost, it would be a tough time for operator to maintain the network.
But at the same time, M2M and IoT technologies are keeping pace into market. I think not all types of devices but still most of the M2M or IoT devices would be using 2G legacy network.