Someone has to pay for it because it’s expensive to develop. There’s a ton of money in Linux just like there is in proprietary operating systems. There are like 4000-5000 kernel contributors and most of them are doing this work on some company’s payroll. There’s an enormous amount of resources going into Linux to the point where a proprietary OS couldn’t possibly keep up.

The real genius of Linux is the economic model, getting companies to buy into it and actually delivering value far in excess of what it costs anybody to contribute. It’s winning precisely because the value proposition cannot be matched.

Except many of those contributions never land upstream.

Hence why we usually with the cloud provider distros.

Example, what powers DGX OS isn't fully available to GNU/Linux users other than a binary blob.