Of course, if you don't pretend that mainframes stopped advancing, you see a different picture. Modern zSeries (or whatever new marketing they've come up with) have multiple 10Gbit interfaces to a network, and can keep them all fed. Not to mention special offload processors for AES and X509 certs, and of course hardware partitioning and virtualization built in. Mainframes are still pretty badass - a lot of stuff that is exciting and new in the server space is stuff that IBM was doing for decades in the Mainframe space.
There is just something very cool about handling something on the order of 10^5 fully ACID transactions per second, while still allowing real time database querying and on-the-fly hardware failure tolerance.
Mainframes are obsolete systems which decades ago all the worlds infrastructure relied on, today they are obsolete systems that all the worlds infrastructure relies on and tomorrow they will be ....
There is just something very cool about handling something on the order of 10^5 fully ACID transactions per second, while still allowing real time database querying and on-the-fly hardware failure tolerance.