The spectrum is also about its dynamic changes through the day, so proportionality across the spectrum as well as within ranges (e.g. within NIR, there are metabolically inhibitory and facilitatory frequencies just 50 nm apart). These are linked to countless physiological mechanisms that are in interaction with each other. So, while we are also looking into more "full-spectrum" electric sources, it is not really possible let alone feasible to replicate daylight.
On the technology side, we are still searching for the best LCD to use and happy to share more in private, but not limiting the spectrum here too much is possible. There are two aspects I can already summarize here: - near-infrared is preserved through the collector and fiber and can be transmitted through the display (but finding the right components is a challenge, as so far nobody cared about transmission properties outside of visible) - opposing the current trend of increasing gamut with ever narrower RGB spectrum, we go for broad spectrum and lower saturation. Aside from physiology, this also has some perceptual benefits, e.g. avoiding the long-term adaptations that make the world look dull as a consequence of wide gamut displays today.