Why does there seem to have been an explosion of activity in AI in recent years?

In addition to the usual continuation of Moore's Law, GPUs have become more powerful and cheaper in the past decade, especially since around 2016. Many ideas in AI have been thought about for a long time, but the speed at which modern processors can do computing and parallel processing allows researchers to implement their ideas and gather more observational data. Improvements in AI have allowed many industries to start using the technologies, which creates demand and brings more focus on AI research (as well as improving the availability of technology on the whole due to more efficient infrastructure). Data has also become more abundant and available, and not only is data a bottleneck for machine learning algorithms, but the abundance of data is difficult for humans to deal with alone, so businesses often turn to AI to convert it to something human-parsable. These processes are also recursive, to some degree, so the more AI improves, the more can be done to improve AI.