There are some routes whose electrification will never be economically viable. So expecting more than 90 % electrification will always remain a utopia.However, since the extent of diesel routes is since decreasing continuously in such scenario, els/dls need to be strategically located so that practice of running diesel locos in electrified routes due to lack of ets/ dts is stopped completely.
While converting dls to els is welcome and will save a lot of infrastructure and money, main question here is proper location of dls so that electrified routes can be served by elocos efficiently.