The progressive weighting of acoustic piano keys is a consequence of the design, not a design feature. All elements of the piano action are identical from key to key, with the exception of damper and hammer size. Lower notes have larger hammers in order to excite the larger and longer strings with all the desirable harmonics, and larger dampers to effectively damp the motion when a key is released. Higher notes have significantly smaller hammers, and in the very top ranges have no dampers at all.
It’s a simple matter of physics that with the same mechanism and leverages, accelerating the higher mass of the bass hammers and dampers takes more force at the key than those at the treble end. This has become the feel that pianists expect, and for this reason the very best digital pianos also try to emulate the progressive weighting of acoustic pianos.