A Micron sign travels across snow Bloomberg/Getty Images Micron crossed $1 trillion in market value this week, a milestone that would have sounded absurd to most investors even a few years ago. The memory-chip business has long been one of the cruelest corners of tech: brutal booms followed by catastrophic busts. I've covered this story before. Back in 2017, I wrote about Sun Microsystems co-founder Bill Joy arguing that the DRAM market had finally changed for good. His thesis was that fewer suppliers and rising demand from cloud computing and AI would reduce the industry's historic tendency to destroy itself through overproduction. That argument turned out to be early, not wrong. Micron shares have soared roughly twentyfold since then. Samsung crossed the $1 trillion market-cap threshold earlier this month, and SK Hynix joined the party on Tuesday. There are fundamentals behind these moves: Samsung made more than $30 billion in profit during the first quarter alone.…