they take it through the people that they normally print through, that is what TokyoPop did before they folded. Such as how Lulu does, it's a matter of setting up everything though a place like that.
Let me sort through this....
1. If DMP takes books to its printers to be printed on demand, that assumes that more than one book of each title is going to be printed. In fact, it assumes that several books of each title will be printed, or the price point per book would be as much as Ebay sales.
2. Tokyopop folded and I don't know many people who actually got their POD books. So we don't know if that was a successful program.
3. DMP would have to set up POD with a press willing to do POD for it and not need any licensing agreements. For example, if DMP were to try to set up POD from a small press reseller like Lulu, basically making the titles available for purchase there, a small press like Lulu would want agreements in place so it could collect part of the royalties as its payment. (I know you didn't exactly suggest this, but in case anyone else would wonder about it...)
4. It would cost DMP significant money and set-up time to create its own POD, even using its existing printer. DMP would have to set up ordering, possibly an entire web site, which, again, would either take someone's time from making new books or result in a new hire. There's no guarantee that POD would generate enough money per year to justify the cost of a new staff person.
5. DMP might not have it in the licensing agreement with a book's publisher to do POD.
6. DMP might not have the license to older titles anymore, meaning that DMP can sell what books it has, but cannot make anymore.
I know you want to think POD is an easy thing, and DMP is just holding back on us, but like any new venture, there's costs and issues that prevent it. Otherwise, I'm sure DMP would be happy to sell us more books.