After 70 years of the crappiest computers ever made, why does IBM exist?

IBM mainframes are very solid. They run critical software that powers everything from credit cards to global reservation systems to government tax and accounting. They’re not sexy but they get the job done and have lots of redundancy and auditing features so there are no interruptions or surprises.

As to why IBM exists today while it’s competitors from 50 - 100 years ago do not, it’s because IBMs leadership has kept the company evolving with current computing trends. They’ve been helped by IBM Research so that there was always someone who knew something about whatever direction IBM was headed, even as the company was pivoting. IBM pivoted from being about punch cards, typewriters, and tabulation (you know, “business machines”) to mainframe computers to PCs to e-commerce to AI and AI governance. You didn’t see Amdahl, Digital Equipment, CDC, or Unisys doing that. HP almost did it and they’re still in business (sort of - they’ve been split). Microsoft is a success story in pivoting from desktop to cloud and AI, but like IBM, the anti-monopoly consent order threw things into disarray for a while.

Disclaimer, I do work for IBM, but my thoughts, especially about the PC, are from my own personal experience. My thoughts and experiences are my own and may or may not reflect the company position correctly.

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I disagree with the OP assertion that IBM makes crappy computers. I started my career using IBM PCs when they first came out, and forty years on, I still miss the feel of that keyboard. When IBM sold the PC division to Lenovo, one of the reasons they did so was that the PC market couldn’t afford the quality that went into IBM computers and IBM didn’t want to be associate with crappy computers. You can see that 25 years later, PC accessories are quite fragile, but they’re so cheap that it’s not a big deal to buy a replacement so no one complains. You can get a high quality keyboard similar to the original PC keyboard but it’s an add-on and will cost you and most people don’t want to pay that.