This position paper on the (meta-)theory of Structural Operational Semantic (SOS) is motivated by the following two questions: (1) Is the (meta-)theory of SOS dying out as a research field? (2) If so, is it possible to rejuvenate this field with a redefined purpose? In this article, we will consider possible answers to those questions by first analysing the history of the EXPRESS/SOS workshops and the data concerning the authors and the presentations featured in the editions of those workshops as well as their subject matters. The results of our quantitative and qualitative analyses all indicate a diminishing interest in the theory of SOS as a field of research. Even though `all good things must come to an end', we strive to finish this position paper on an upbeat note by addressing our second motivating question with some optimism. To this end, we use our personal reflections and an analysis of recent trends in two of the flagship conferences in the field of Programming Languages (namely POPL and PDLI) to draw some conclusions on possible future directions that may rejuvenate research on the (meta-)theory of SOS. We hope that our musings will entice members of the research community to breathe new life into a field of research that has been kind to three of the authors of this article.

翻译：本立场论文聚焦于结构操作语义（SOS）的（元）理论，其研究动机源于以下两个问题：（1）SOS（元）理论作为研究领域是否正在消亡？（2）若是，是否可能通过重新定义其目标来复兴该领域？在本文中，我们将通过首先分析EXPRESS/SOS研讨会的历史、各届研讨会的作者及报告数据以及其主题内容，来探讨这些问题的可能答案。我们的定量与定性分析结果均表明，对SOS理论作为研究领域的兴趣正在减弱。尽管“一切美好终将落幕”，我们仍努力以乐观基调结束本立场论文，通过回应第二个动机性问题。为此，我们利用个人反思，并结合对编程语言领域两大旗舰会议（即POPL和PDLI）近期趋势的分析，得出关于可能复兴SOS（元）理论研究的未来方向的结论。我们期望这些思考能激励研究界同仁为一个曾对本文三位作者厚爱有加的研究领域注入新生。