Assuming demand does not asymptote as we approach singularity.
Which it to say, if models eventually do useful work, demand for substrate will continue to outpace production. I don’t envy the fabs that have to forecast how much memory the world will desire in 2030
This is a supply constraint and requires no assumption about demand - HBM packaging capacity constrains the amount of wafers that can go towards HBM (regardless of price in the near term), and excess wafer capacity will be dumped into DDR5 and crash DDR5 margins.