How to encourage self-archiving of preprints in science? As the background, I am a graduate student in high energy physics, mainly theoretical physics. Recently, I have sen that there are a few scholars who don't put the preprint versions of the paper in the preprint servers such as arxiv. I must add the fact that for many of the journals the self-archiving of the preprint is allowed, and I see no point for not putting the preprint version submitted to peer review on arxiv. I have seen that there are some old researchers and also some not so old ones who don't put the preprint versions of the paper on arxiv and sometimes make it difficult for some papers to be read. Hence, the question would be on how to promote open access and convince people to be opened within this direction.
From what I see, some organizations are solving this by making self-archiving mandatory. In the UK, research funding bodies are now starting to use only open-access publications to assess the quality of research. As a result, the universities are starting to require their academic staff to self-archive publications. Also, I've seen a conference organizers discussing whether they should require the authors to self-archive the accepted papers.