It feels like they're double dipping. Unpopular as it might be, I'd guess people would be more than willing to pay extra so that they could shitcan this "feature".

I don't think it's arbitrary. You're paying for the (vehicle, driver) time and distance and the closer your are to vehicle the shorter the trip. If the vehicle is far enough away to make it vary greatly just cancel. The seemingly arbitrary charges and price volatility are not supposed to start until after you're in the vehicle. This may just be a bug.