They are almost 100 years old which is an accomplishment. I wonder how many they have left. I bet a big chunk of that depends on companies still running AS/400 systems.
See page 17: https://www.ibm.com/annualreport/assets/downloads/IBM_Annual...
(AS/400 is midrange. They are called something else now, I heard. Maybe I-series.)
A lot of those indispensable infrastructure systems we all depend on, such as insurance, income tax, etc., run on mainframes, as they have for decades now.
So don't diss big iron / Big Blue.
I, for one, hope they have many years left, though I guess they could do with improving their corporate culture and business practices some.