Have useful skills. In the worst case scenario it will come to trading services or products. I.e. you are a good web developer and can build a website for a car

Have useful skills. In the worst case scenario it will come to trading services or products. I.e. you are a good web developer and can build a website for a carpenter who will fix your roof in exchange. Some other might know how to fix cars or mechanics. Learn skills that will become valuable in such a scenario. The best investment is your own skillset. Actually, the "workers" as you call them might be in better position in this scenario as they usually have better and broader knowledge of fixing every day stuff than let's say accountants or software engineers might have.