The Bentley concept illustrates better than words what happens when shared-platform imperatives so-called hard points such as the size of an engine or height of a seat or dimensions of a gas tank are the primary drivers of design.
The instructions were in Italian, so I wasn't sure exactly what its features were, but I believe you could adjust the height, automatically raise and lower the seat and lid, and apply a sanitary paper covering.
Its cantilever mechanism between the seat and seatback required no calibration of tension no matter who sat in the chair, regardless of height and weight.