Moving to a different node (or even a different fab of the same node) requires significant engineering effort. Meanwhile, we are talking about chips which cost

Moving to a different node (or even a different fab of the same node) requires significant engineering effort. Meanwhile, we are talking about chips which cost less than a dollar. Heck, some chips even cost way less. For example, Diodes Incorporated's 74LVC1G06FZ4-7 currently sells for $0.016 in quantities of 10.000. It's an absolutely trivial component logic-wise, so there is nothing to gain by shrinking the die. In fact, due to the current capabilities and ESD tolerance shrinking it would make it worse. Chips like that are never going to move to a different node - they will be produced until the fab breaks down or becomes unprofitable, at which point the chip is discontinued.