Yes, prices are all over the place and, despite being a great tractor are hard to sell. If they are in super condition they will bring a little above average price and if in average condition a low price. Probably just not enough around to have the excellet quality widely-known.
They are also on the light side, weight wise, and smaller in cubic inches than commonly expected in a tractor of this size. As well, the kubota name appeals more to the upscale hobby person that is under financial pressure at the moment. If I saw the right one at the tight price I'd buy it myself.