It costs more because it's less dense than DRAM - the same transistor count that produces 2GB of DRAM can only fit a fraction of that in SRAM because it's 6 transistors per SRAM cell vs. 1 + capacitor for a DRAM cell.

Power usage is also generally worse since the SRAM cells use continuous power to hold their state, while DRAM cells only use power during read/write/refresh (relying on the caps to hold their charge for a short time while not actively powered).