[sidpatil]

> If programmer time is more valuable than machine time

This is probably not true in industries such as banking, manufacturing, agriculture, etc. I worked as a field engineer in a food processing plant once, during the peak season for the crop being processed. The plant manager told me that downtime could cost the plant up to a quarter million USD per day.

> Why do we accept that our hardware is unrelaible and then spend so much effort making our software tolerate failure?

From what I understand, the whole point of mainframe design is to tackle the issue that hardware is unreliable. Mainframes feature many hardware redundancies, moreso than a commodity rack server.

> I do not know whether or not mainframes are the right solution, though. I don't really know anything about them. I don't know whether or not the architecture is the correct approach.

Mainframes are designed for throughput, not performance. They are good at things like transaction processing, not machine learning.