You replied "Letting perfect be the enemy of good" several times in the comments here. I think the sentence works against the arguments you're making:

Perfect is the promise of a climb-everywhere-wheelchair. It's hypothetical, dreamed up, and causing people to forego the immediate and good solution (ramps).

You are also making the assumption that the hypothetical climb-everywhere-wheelchair is better than a ramp.

The ramp is easier to make safe, and so we need to ask about safety if it works most of the time. This also gets into maintenance, the robot with moving parts is expected to have more parts to break.

The ramp's batteries will never go dead (or if they do it doesn't matter since they are only for lights anyway?).