The "legacy" theory is attractive but unfair. Ultimately, image reproduction is about controlling perception and human brightness perception is non-linear.

You should do any calculations in linear space (and possibly with a temporarily higher bit depth) but a linear display would not be desirable.

Imagine having a room with 10 independently controlled LEDs of equivalent brightness to a 10-watt incandescent lightbulb. Try to visualize the difference from going from 0 (pitch black) to 1 light, to 2, and then imagine 9->10. If you try this IRL you will notice that human brightness perception is very non-linear. To get the most bang per light switch, we need to make the later lightbulbs brighter to get the same punch. This is what monitors do with their bit depth.

It makes good sense for human perception to be non-linear: Earth has a very wide range of brightnesses we need to live in, and the difference in information we can acquire from being out in the sun vs. in the shade is not commensurate with the difference in brightness.

If you are in a very, very dark place (not a city at night) you will experience a very distinct non-blackness. Your eyes (brain?) are turning up the gain to try and extract information. (I don't know if this happens in a perfectly dark place.)

Uh sorry this was rambling. I should read that article...

Oh yes, human vision is non-linear, also adapted to a wide variety of situations (just try using a digital camera and see how several adjustments are needed and the eye does this "automatically")

But it's hard enough considering human non-linearity without adding any other non-linearities along the way (like the CRT ones)

It's true: although human perception is nonlinear in a similar fashion (logarithmic/expt) the exact way CRTs (and LCDs) transform is not based strictly on human perception (as far as I know). It is interesting to think of how it could be improved but I don't have any answers right now.