Banks run the world, IBM mainframes run the banks.

>IBM mainframes run the banks.

And the airlines, and the logistics companies

That's a bit unfair to the insurance companies. They have a pretty big say in what happens and also run mainframes.

And mainframes run on concrete floors, maybe construction companies run the world by that logic?

Mainframes aren't a big truck, they're a series of concrete floors.

My usual comparison is with cargo airplanes.

This is becoming less true over time.

many of the most core US IT infrastructure projects- government and commercial- depend on IBM 360 assembly code or another IBM system, written decades ago that has been repeatedly scaled to handle the increase in load.

Two I can think of: SABRE and the IRS. See more here: https://www.nextgov.com/cxo-briefing/2016/05/10-oldest-it-sy...

Personally I have a ton of respect for production systems that can be scaled in place for 50 years. But I don't have any interest in learning to run IBM mainframes or code for them- I'm preparing for lots of contract work in 2037.

> And their mainframes, underhyped to the extreme, that more or less still run the world.

More or less, but less and less. Many a bank, airline, etc. has had or has or will have a "digital transformation"/move to cloud/rewrite apps/websites to actually be usable/etc. project to switch away from legacy stuff handicapping them to a more modern leaner tech stack. Mostly because they got shown by newer, leaner competition how it's done (neobanks, low-cost airlines) so finally there is some incentive. And of course the added benefits of commodity hardware (as a Service) being much more easily replaceable and scalable. If you're a big bank/airline, why would you spend billions on mainframes from a single vendor you're beholden to, with all the staffing problems (nobody knows this stuff so hiring is a nightmare), specced for the highest possible load you might get? Instead of throwing it on AWS which "everyone" knows and can scale up/down based on demand. Migrating isn't easy or cheap, but it makes so much sense.