While this generation of VR has not (yet) added the olfactory sense to their set of outputs, this does not mean that older systems have not tried.
Movies tried to add the sense of smell in 1960 with the movie Scent of Mystery. At specific times in the movie, smells were sprayed into the audience. Some theatergoers complained that the smells were overpowering, while others complained they could not smell them at all. But everyone agreed that the movie, even with Elizabeth Taylor, was not worth seeing, and this technology quietly faded away:
Morton Heilig built the Sensorama in 1962. Only a single viewer at a time could experience the short films, but the viewers were exposed to all the senses: Stereoscopic 3D, smells, vibration, wind in the hair, and stereo sound. Today, 4D movies at many major theme parks are its closest relatives.
Heilig did attempt to create a large audience version of his immersive films, which included elements from Sensorama and the Cyclorama. He called this the Telesphere. The large field of view, stereoscopic 3D images, and vibrations were designed to create an immersive experience.