Sigh.... Dross survey with dross conclusions...
The stats in both surveys are skewed on the basis of people talking to mainframe shops in the first place. It is like the old segfault.org joke about object oriented programming where the cobol programmer asks "what is an object"?
Virtualised infrastructure (aka private cloud) will replace mainframes, however it will need to grow up quite a bit to that task. Just shipping a big box which can do virtualisation the way Cisco does in their California lineup does not a mainframe make. You have to have a database stack, transaction middleware stack, a workload stack, etc and all of that integrated to the virtualisation, load management, etc. You also have to have a lineup of suited "bioware" to support the customer through using it.
The sole player besides IBM and Unisys which is closest to having this out there today is SnOracle which funnily enough deplores the whole cloud idea. Everybody else is years away from there. No cloud offering comes even close and it will not come even close anytime during this upgrade cycle. Next or cycle after next upgrade cycles from now (5+ years at least) maybe, but not this one.