Even when open source is “attributed”, that is usually done in the laziest and bare-minimum way possible (like being buried multiple levels deep in some “Acknowledgements” item, that simply displays a 45 page text document with unzoomable and unsearchable text that casually lists the dozens of open source libraries used).

Unfortunately there are a lot of people who really will do the bare minimum and take everything they possibly can from projects and give absolutely nothing back.