So Ford has decided to follow Citibank, Virgin Atlantic, DKNY, French Connection and a fair few more over the years, and bailed from Japan. Struggling since inception, Ford was selling something in the order of 5,000 units a year. Compare that to Toyota Tokyo which sells something around 60,000 per month. The are no import tariffs and the days of parking signs saying "No Foreign Cars" are long long behind us. There's no reason to fail short of actually trying.
Ford had simply decided not to address the market. Presenting left-hand drive cars in a right-hand drive market was never going to be a highly successful strategy. With a market leading UK right-hand drive range, it only imported from the US. Added to this, the minimal dealer footprint and near invisible marketing really didn't generate confidence (or buzz) in the country. Essentially there just wasn't the customer satisfaction to build a viable business or attract an independent dealer network.
Compare this to the customer service of a Japanese carpark where you can pay on exit at the barrier, or you can pay before the barrier, or you can pay the chap who is there to help, or you can pay on the right, or on the left (for those Ford owners with the wheel on the wrong side) or your ticket can be optically linked to your number plate so that you don't even need to stop at the barrier. I actually like Ford, the GT40 being one of the greatest machines of all time, but if a humble ticket barrier can do it, why is it that an engineering empire can't?