While this is true of LCDs, OLEDs have basically no draw latency, so conceivably they could directly update as the frame buffer was populating like a CRT if the gpu driver and OLED driver allowed it. This would still have tearing though for a modern game, so it is likely that it would need to buffer and draw entire frames at a time, which could still give you only 1 frame of latency. Most of the older games were not updating the positional information of sprites between frames (just using scanlines for raster effects) so there was already 1 frame of latency on input updates.