Yet, despite that, a creator named Lodef Mode has recently developed a cartridge named MovieCart that allows the old machine to do just that (as spotted by techeblog & Hackaday!).
As Hackaday notes, the quality of the video and sound quality isn't necessarily the best, with the image, in particular, being subject to the color limitations of the console and a resolution of just 80×192. But it's still a fun project nonetheless and one we imagine will interest Atari fans who likely never considered this a possibility.
MovieCart packages, including a fully assembled PCB board, an SD card featuring "Night of the Living Dead", and cart labels, were available to pre-order on Tindie for $24.99. However, they appear to be sold out at the moment. There is a waitlist option, however, should you want to be alerted when they're back on sale.