Massive migration to all-IP networks?

Latest Heavy Reading report states that telcos are getting ready for the carrier network transformation — from CS / ISDN technology to all-over-IP.
It seems we are facing huge investments in IP network transport equipment. The thing that will probably go in parallel will be investments in new IMS service platforms. Most important reason of network migration seem to be the OPEX savings (softswitch/IMS solutions are cheaper to run and maintain than PSTN/ISDN exchanges) and new innovative applications and services.

Less and less people believe that a new killer-app will emerge to become a driver for the migration. Most of IMS services can be realized now, without migrating the whole network infrastructure. Some of them can be deployed on IN platforms, some — on IMS application platforms interoperating through media gateways with CS-based networks.
So, in my opinion, the migration will not happen so soon, at least in the emerging markets. New and/or small operators will for sure decide to build IP-based infrastructure but incumbents and large GSM operators are not so eager to invest so much so fast...