That is correct. The final run sold out fast and the aftermarket has priced these out of a reasonable price range. Time will tell if supply and demand will change this situation. I suspect there is a relatively small number of people willing to pay the high premiums right now, and the prices will fall back into a sensible range soon enough.
At this time, Oppo UDP-203 cannot stream DSD content via Network, you can read more regarding this limitation in the following thread: OPPO UDP-203 and UDP-205 now Roon Ready. As far as I’m aware, USB/HDMI connections do not have this limitation. I hope this helps but do let me know if you have any other questions!