Most linux distros require that software they distribute is open source, and link to the home pages of applications, so effectively donations are the only way to pay for those. There are paid distros (which are almost always about support, there was a paid GNUStep distro though many years ago).

On the other hand, Steam et al are app stores where developers can get paid.

Open source doesn't mean free.

> On the other hand, Steam et al are app stores where developers can get paid.

Yes, this is exactly my point. App stores have a reason to exist. They provide discoverability and a streamlined way to monetise your app, something that is sorely lacking in open source projects. A case in point for example is Krita, which is published as a paid app on the Microsoft Store. The revenue generated by the sales goes to fund the development of the project. Linux needs an equivalent.