That's an interesting idea and yes, I think it would help. It seems you can find cable sleeves in this style, though I'm only seeing them in bulk.
Yeah, I've seen things like that. The problem there is that the colors cycle. The point is to provide an unambiguous visual cue of where along the length of the cord a given section of cord is. If the colors cycle, then two locations can have the same color, undermining the utility of the cue. A few other products come with a gradient on the cord, but the endpoints barely contrast; say a light yellow-light orange gradient.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.