Why don't big tech companies unite to build an OS?

Why does replacing Linux seem like a good idea to you? That would mean rewriting billions of lines of code written for Linux.

Operating systems include lots of libraries and drivers. Programmers write code that depends on OS-level functionality.

Before Unix every computer manufacturer had their own proprietary OS, specific to their hardware. While that did lead to some innovation and competition, it also made changing hardware platforms risky and expensive.

Rob Pike wrote about this 25 years ago:

https://doc.cat-v.org/bell_labs/utah2000/utah2000.pdf

They have. It’s called Linux.

I'm glad they haven't. If they did, it wouldn't be free and open source like Linux is.

Also, there are myriad reasons why big tech companies wouldn't unite to build anything, let alone something as complex as an OS.

Why should it be the big tech companies doing that?

Serious questions: why and what's the point? You can pretty much mold Linux into whatever you want.

> I think it needs a replacement for serious cloud and AI-related tasks.

Why? I use it for both and it is expressly excellent at them. With configuration and automation frameworks on top like NixOS or k8s, you can build just about anything.