Re: So how do "modern monitors" do it?
That's exactly the point of the recent changes. sRGB has a very limited gamut - it's a lowest common denominator colorspace, but what you get when you specify #FF0000 or use the rgb() function, which are defined as using the sRGB colorspace.
The new functions allow you to choose wider gamut spaces, which will be handed off to the system color management engine for rendering. It's not really a question of brightness - display-p3 for example, supported on iPhone displays, uses the same D65 whitepoint as sRGB - but it's more to do with extending the range in certain directions. You'll be able to make an orange, drawn in SVG with gradients, just a bit more orange.
Once you get into the details of colour management it's horrendously complex.
Biting the hand that feeds IT
