A lot of companies still pay $5-$20mil for these things so they can continue to write COBOL... COBOL itself, being an interesting beast...
What's funny is the way a lot of the software packages for mainframes are licensed... rather than a per-seat, per-socket, per-core fees... they have per-cpu-cycle fee. So the more you use their product, the more they bill you every month. Absolutely brilliant way to extort money from your customers.