The only reason why most old CRT displays were calibrated for a 6500 K color temperature was because the red phosphor had a lower efficiency than the others.
Using a white with less red and more green and blue allowed the vendors to advertise a higher brightness for the displays.
The same reason applied to fluorescent lamps. Choosing 6500 K allowed the vendors to advertise a higher luminous flux at a given electrical power.
Nowadays there is absolutely no technical reason to use a white with the 6500 K color temperature, even if the low-quality LED lamps with a single orange phosphor still have better efficiency when emitting more bluish light, but those have a too low CRI to be an acceptable lighting solution.
Nevertheless, for the lighting of my home I do not like a too yellowish white, so I use LEDs with the 4000 K color temperature, which, unfortunately, are much harder to find than those with a yellowish 2700 K or a bluish 6500 K.
Using a white with less red and more green and blue allowed the vendors to advertise a higher brightness for the displays.
The same reason applied to fluorescent lamps. Choosing 6500 K allowed the vendors to advertise a higher luminous flux at a given electrical power.
Nowadays there is absolutely no technical reason to use a white with the 6500 K color temperature, even if the low-quality LED lamps with a single orange phosphor still have better efficiency when emitting more bluish light, but those have a too low CRI to be an acceptable lighting solution.
Nevertheless, for the lighting of my home I do not like a too yellowish white, so I use LEDs with the 4000 K color temperature, which, unfortunately, are much harder to find than those with a yellowish 2700 K or a bluish 6500 K.