That’s what you think, though, you didn’t design the printer. I assume you don’t have a background in color theory or chemistry or whatever else you need to produce ink.
For all you know, the black ink isn’t really a perfect black and the color inks are used in conjunction with the black ink.
I also think a lot of people are just being cheap about it. It’s just not a big deal.
In my experience a color inkjet printer makes a much better print than a black and white laser printer. If you are willing to sacrifice print quality then buy a black and white laser printer.
For all you know, the black ink isn’t really a perfect black and the color inks are used in conjunction with the black ink.
I also think a lot of people are just being cheap about it. It’s just not a big deal.
In my experience a color inkjet printer makes a much better print than a black and white laser printer. If you are willing to sacrifice print quality then buy a black and white laser printer.