As mentioned, you're linking to a pull type TRANSPORT disc, NOT an antiquated, obsolete, semi-useless, worn out "drag disc" such as "someone" seems to think of as valuable and efficient. These transport disc's are rigid frames, somewhat similar (in that regard) to 3-point disc's. The old drag disc's wallow and undulate with irregulareties in soil surface, and leave a relatively "un-level" surface, as well as a poorly prepared surface (relative to rigid frames which make the soil finish level comply with the disc as opposed to disc complying to soil)
His rather novel idea of old drag disc's using less fuel is utter nonsense. Same tractor pulling 2 different styles of disc's, one using less fuel than the other equates to LESS WORK PERFORMED....It's just that simple. A disc with worn out blades doesn't cut as deep or mix soil nearly as well, which is.....LESS WORK PERFORMED.
There hasn't been a drag disc built by any major manufacturers since the VERY early '60's. REason being, they're inefficient, poor performance, and NO "new" market for them. That's because there are FAR better options.....ie, rigid frame transport disc's, 3-point disc's...... Deere TRIED to market a transport disc in the '50's and early 60's that had floating gangs. It was unpopular back then and was discontinued due to near nonexistant sales.