In the US, there is a one year grace period for inventors to file a patent application after public disclosure. Such disclosure does prevent you from obtaining patent protection in most other countries. That said, how do you know that other researchers have published without filing for patent protection? Patent applications typically take 18 months to publish after filing. A new technology published in a journal may easily have a patent application filed without your knowledge.
To address questions in your comments, once the grace period passes, you have no control over your technology so you can't sue others for commercial use. Unlike patents, there is no requirement for an academic publication to fully enable a new technology so you might protect some aspects of your ideas. However you won't make many friends trying to do so. As the expert in your technology, you are in the best position to pursue and patent important improvements.
Academics publish for many reasons other than commercial reward. Career growth in academics is based substantially on quality and quantity of the author's publications. Publications, especially in well respected journals increases the researcher's profile within their field which may lead to collaborations and further career progress.
