Another guess too is that you may not see many CPO cars on the web now - but you can still buy them by visiting your local Tesla store. Let's not speculate - just get in there and ask what they have available. The web does not define the entire inventory. For the past year, there have always been "cars available" if you asked. Now, they just have put some of them on the web.
I asked two OAs at different stores and got the same response that the CPO inventory is what we see online. No other un-listed hidden cars.