This used to be true, but your rant, as I pointed out in my post weeks before yours was written, seems to be a year or two out of date. This really doesn't seem to be true anymore of (at least) some of the professional-level inkjets. Less than 20 bucks gets me about 800 pages of black [<2.5 cents per page]; that's actually better than some lasers ($80 for a toner cartridge that gets you perhaps 3000 pages on the mono laser I had before my current printer [about 2.6666... cents per page]). And that's the less cost-effective of my two ink cartridge options.
I have an HP Color LaserJet 4700dn (the "dn" is "duplex/network" included).
Here are some stats from the printer's web-based "Device Status" pages:
Black Cartridge 61% 3593 printed, est 5619 remaining
Cyan Cartridge 63% 2900 printed, est 4937 remaining
Magenta Cartridge 69% 2952 printed, est 6570 remaining
Yellow Cartridge 75% 2952 printed, est 8856 remaining
Historical Printer Coverage:
Black 5.5%
Cyan 5.7%
Magenta 3.4%
Yellow 3.7%
Depending on how the usage overlaps, I should have at least 4937 pages left before the first cartridge needs replacement. Since the install date is 2007-11-10, those numbers represent about 13 months of use so I should have approximately 20 months before replacement is necessary. That cartridge is $100 from "LD Products", a printer supply reseller that I've used for years and always has a good price and excellent customer service. So that's 9000 b&w pages for $100, or about a penny apiece. The color printing costs about 3x that, close to four pennies a page. Of course, for me the printer and supplies are a business expense.
I print mostly b&w and my wife prints mostly color (she prints web pages the "easy" way, while I will set the printer driver to grayscale mode for speed and ink conservation).
YMMV.