I have a mild but potentially wild speculation that it might be the internet. The internet allows workers to communicate not just within the company but within the broader ecosystem of work. People are more and more aware of what a raw deal they're getting by executives and companies, and are becoming more and more hostile because they're aware of how hostile companies are to them. Additionally, companies are picking up eye-tracking technology and other hyper-controlling tech that was never feasible a generation ago, leaving employees feeling increasingly taken advantage of.