In last few years, market of CTI ( Computer Telephony Integration) Board has been steadily declining, though I am not aware of any market survey except disclosure on casual discussions in the field. While low cost CTI boards were still being in use for many on-premise IVR systems, but I have not heard about any big sale or project involving high end CTI boards.
While the sale of CTI boards were already declining, introduction of PRI delivery using SIP link by some telephone service provider might hit the final nail in its coffin! So, suddenly, CTI hardware is no longer required to run a scalable enterprise level IVR Systems.
I am assuming, in future every large IVR systems will be based on host computer doing all telephony processing as well as processing any voice applications! Most probably, it will make life much easier for IVR developers by eliminating having to install any hardware in inside Server-PC or rack!
I still feel, CTI cards are much better as dedicated system to interact with telephony systems while host computer does other computations as per voice application. But then, with increasing computational power and decreasing cost of servers, I should not complaint the new development, specially as it reduces total cost of ownership of IVR system now!
With Asterisk and SIP Connectivity for PRI, I do not see anyone would use analog CTI cards anymore, except may be places where SIP based PRI delivery is not possible!
I assume, very large enterprises will still be using Media gateways from Dialogic or other enterprise level hardware like Keygoe Series from Donjin for really, really big IVR Systems. Except them, with availability of Cloud Telephony services and Asterisk/HMP with PRI on SIP, no one will use CTI cards anymore!
So, most probably, with introduction of SIP based delivery of PRI lines with 20 Voice channels, use of CTI boards in IVR( Interactive Voice Response) system might become history. In future only Asterisk and Dialogic HMP will be used!