What do you think will be the next product everyone wishes they had bought earlier?

A few months ago, DRAM and SSD prices surged. What impressed me wasn’t the price increase itself. it was the people who saw it coming months in advance. They seemed to understand supply chains, industry trends, or demand shifts long before the news caught up. That made me wonder: What do you think is the next product, material, or commodity that could become difficult to get or dramatically increase in price over the next few years? More importantly, what signals are you watching? I’m less interested in lucky guesses and more interested in how experienced people connect the dots before everyone else.