Do they publish source code or binary drivers? If it's the latter, the article points at why they might not want their competitors to read their source code: the drivers matter a lot, and starting from theirs might well cut the development costs for a competing product in half.
Realtek drivers are GPL’d, but have a reputation (especially Wi-Fi dongles) of not following the coding standard of the Linux kernel and of low code quality, making them unacceptable for the upstream kernel. A driver often goes through a lengthy cleanup process by the community, first by existing as a “staging” driver in the kernel with incomplete features and unstable code, and later the code is gradually refactored before it’s finally official.
