Speaking from personal experience, there are two ways you can go when making this type of stuff. You can just do a bunch of improvs and burn them to CDRs or you can spend ages editing your improvs together into more structured "songs". I take the latter route but I often wonder whether it's worth spending two years putting together an album that nobody will buy, given that most of the raw improvs sound pretty satisfying on their own.
One of the other differences between my personal experience and what Machinefabriek does - time-wise - is that he has a much more punk rock attitude. I spend months and months tinkering with Max/MSP, building the exact instruments and effects I want to use, whereas he uses whatever is at hand. I think most of his stuff is done with guitar pedals. Apparently all of his computer work is done in Macromedia Soundedit - a beautifully simply, utterly obsolete audio editor for OS 9!
Anyway, I think he is able to produce precisely the sound he is going for by working with simple tools, within strict parameters and simply not over-thinking it. Why this approach works for him and not others who take a similar route, I don't know. Maybe it's just a case of aesthetic focus.