Softswitch vs IMS

When you talk to telecom equipment vendors, they say that the era of softswitch technology ends, and softswitches will soon be replaces by mature IMS platforms.
However, instead of abandoning softswitch technology, telcos deploy more and more of them every year. Do they give up IMS instead?

First, in this post, let's say what softswitch and IMS are.

IMS technology is a further development of softswitch technology. Softswitch architecture separates service control from service access, and uses an IP-based core layer in the switching network.
All-IP IMS technology uses IP network to access terminals network. It also uses IP-based protocols (including SIP — Session Initiation Protocol — and Diameter) for signaling purposes.
Softswitch is a voice solution whereas IMS is designed for multimedia capabilities.

Softswitch is more or less a software-based version of traditional digital exchange. It provides IP telephony service. In IMS architecture, it is analog to CSCF (Call Control function). Softswitch implements service logic to control external trunking gateways, access gateways, and remote access servers. Softswitches run on commercial computers and operating systems, and they provide open applications programming interfaces. Also called a call agent or a media gateway controller. Softswitch cooperates with SS7 network. It can either work with PSTN phones or SIP phones.

IMS is a complete architecture that contains application servers, call control function, home subscriber servers, media gateways and servers etc. Softswitch can be incorporated into IMS during the process of network evolution.