Is Mainframe technology is evergreen technology ?

Its said in late90's that last mainframe machine will be unplugged in near future and the same is being repeated again and again.... Its hard to migrate or move such old legacy applications(but not impossible). and yes in future world may not need mainframe developers but they need mainframe machine still... coz mainframe is high and speed and security where no other server can beat or atleast reach ... so we need mainframe admins in future but not much developers...

Not really in my opinion

Not Necessarily.... but it all depends how company keeps its pace on emerging technologies and how effectively they can manage with cutting edge technologies with talented resource pool.