That also isn't illegal. A business can choose to artificially restrict supply if they want, there's no mandate that they must meet demand.
It only crosses into illegal territory if multiple companies get together and secretly agree to cap production to keep prices high. Then it becomes collusion. It also becomes illegal if there's a monopoly power that is intentionally constricting supply to specifically stop a smaller competitor or lock them out of the market.
The hard part is how do you prove Samsung, SK Hynix, Micron are acting as a unified cartel when there obviously isn't going to be a paper trail for secret meetings.