Server sales are still going strong due to demand for cloud-based services and IoT hype. At the same time, the amount of RAM per server is increasing. On the mobile side of things, sales may be down but demand for the newest memory on the newest fab process is still high as ever and memory manufacturers are still in the process of migrating their DRAM fabs to sub-20nm processes.
When it isn't supply chain disruptions causing prices to go up, it is a DRAM manufacturer bankruptcy. The stupidly low prices people get accustomed to every few years when DRAM manufactures are caught between having to choose between shutting down fab lines due to over-stock when sales slow down or lowering prices below cost to clear inventory just to avoid shutting down lines (fab shutdowns and restarts cost millions of dollars) aren't sustainable. If you think current prices are bad, it would have been much worse if the low prices persisted and we had another manufacturer bankruptcy. The last time a bankruptcy occurred, memory prices tripled.