Liberapay is not the only platform that allows for free software to be funded. Here are two projects that are very well funded on Patreon. The platform itself is obviously not open source, but the projects themselves are:

https://www.patreon.com/godotengine

https://www.patreon.com/mastodon

There are so many good projects on Liberapay:

https://liberapay.com/Mastodon/

https://liberapay.com/archiveis/

https://liberapay.com/davidrevoy/

https://liberapay.com/GIMP/

https://liberapay.com/UBports/

https://liberapay.com/F-Droid-Data/

https://liberapay.com/pixelfed/ (open source federated Instagram)

https://liberapay.com/SFTtech/ (open source Age of Empires II)

https://liberapay.com/Telegram-FOSS/

https://liberapay.com/phpMyAdmin/

https://liberapay.com/Framasoft/

https://liberapay.com/matrixdotorg/

https://liberapay.com/Krita/

https://liberapay.com/Nextcloud/

https://liberapay.com/ReactOS/

You can work for companies that will pay you to develop FLOSS that supports their products. This is where most of code in Linux comes from.

Making a good FLOSS product and relying on donations alone would be a foolish career choice, agreed. You need to be creative on how you earn income, and it can be done. That being said, if you are looking for the easiest way to make money as a developer, FLOSS is not the answer, for sure. You need to have a passion for it.

>Weekly income is no more than 100€, that's what like an hourly rate of top end freelance developer (which really a lot of these guys are).

You do realize that's per donor and a recurring payment.

It's not per donor. Their total transfer volume last week was €1,589.34 according to the website. As far as I can tell, the only project with more than €100 in weekly income is Liberapay itself.

EDIT: I see now that they cap donations per donor and recipient at €100 per week, but it doesn't seem like anyone gets close to the cap.

There may be donees who receive more than that but don't make the amount public, but you are correct about the total volume.