I see. This would probably work, but there's a little catch. Logitech wheels indeed use a ramp force FFB effect to create the soft-stop (DFP definitely does, not sure about G2x/DFGT). However, when the wheel is turned past the soft-stop, it still transmits the axes position data. If LFS limited the wheel range just by FFB, turning the wheel beyond the soft-stop would turn the wheel in game, making LFS adjust the wheel's calibration which in turn would lead to all sorts of unwanted effects.
When the range is limited via Logitech driver, the driver takes care of this and clamps the X-axis range accordingly.