Internet of Things (IoT) has emerged as an umbrella term to describe connecting smart everyday objects (such as washing machines, toilets and sound systems), sensors and industrial machines to the internet. While IoT devices hold potential to greatly enhance quality of life through automating and optimizing mundane tasks, there are a great deal of security and privacy challenges. For this reason, practitioners and academics have explored various ways to enhance the multi-layered security of IoT devices. One of these methods is obfuscation, which has been successfully applied to make accessing devices more difficult for adversaries. In this study, we systematically processed the literature on applying obfuscation and diversification to improve IoT cybersecurity (81 articles) and clustered this research according the obfuscation target (code, data, interface, location, traffic). We then conducted a follow-up bibliometric review of the entire research profile of IoT cybersecurity (3,682 articles) to understand how these obfuscation and diversification approaches relate to the general cybersecurity landscape and solutions of IoT. We also derive a comprehensive list of benefits and shortcomings of enhancing IoT security through diversification, and present points of departure for future research.