^when it says "out-of-print" in CDjapan, it really means its just not available anymore. They can get a new stock if they looked from their sources more, but thats too much of a hassle and counter-productive unless there was a high demand for it.
For instance, Yuna Ito's Losin' You and Stuck on You singles were limited to 50,000 copies each, however they only sold less than 10,000 or something. There are 40,000 more to be grabbed in various retailers.