Strongly disagree with you bob. Been in the print business long enough. While it may be the tale with RGB print, CMYK is a different monster altogether. Sure, your wide-format printer MAY interpret 100%K at TRUE black (I have a smaller machine that can) and exchanges it for the right balance of black, if you run just 100%K black, it will look somewhat washed out. The reason is 100%K is intended to be mixed with other colors to get true colors; It needs other colors to get good blacks.
And yes, there is such things as True Black, Rich Black, Cool Black, Thick Black, etc. If you don't believe me, walk into any offset press that has been in business for more than a year or two (And who don't run theses 'push a button to start' presses) and they'll clear it up for you. 100%K Black on white paper (Especially a nice press quality gloss) will look like a washed out gray, and look awful next to the vibrant colors.
I think the biggest problem in the world is that we made the mistake of 2 common color formats; RGB and CMYK. A lot of the RGB mentalities carry over to CMYK because we all design in RGB at some level digitally (-- If you design in CMYK, please let me know; I want the CMYK monitor and vid card.
--) When I started in the print business, it took me a while (and some repeated pesterings from my pressman) that RGB black is nowhere close to CMYK black; That RGB black in photos can be evil too; that 100%K is not a substitute for Real Black either. I am much wiser now however.
As for your metaphor for paint; The last time I checked, spray can car paint 'black' was manufactured to be true black in itself, and not intended to be 'mixed' for accurate color reproduction (For the spray paint cans). Actually, used to be around a couple franchise paint shops, and when they do mix their own colors for painting, black is a mix too, and their black does look a bit faded, compared to the intense blacks on a car.