I have nothing to do with Telltale (except being a huge fan of their amazing games) and therefore know absolutely nothing, but here are examples for other Telltale seasons:
Wallace and Gromit's last episode was released on July 29, 2009 and the disc will ship in January 2010.
Strong Bad's final episode was released on December 15, 2008 and my copy of the DVD was shipped on June 30, 2009.
Sam & Max season 2 saw its DVD released at the end of July 2008 (though I seem to remember receiving it a lot later, possibly because I added the case files and a signed print to my order), when the last episode was available on April 15, 2008.
Finally, Sam & Max season 1's DVD started shipping mid-July 2007 (the retail version by The Adventure Company was released a shortly afterwards) when the last episode had been available since May 7, 2007.
So, it looks like the time frame between the last episode and the DVD varies between 2 1/2 and 6 1/2 months, which tells us... absolutely nothing about TOMI!
Personally, I don't care as long as I can play the downloaded episodes whenever I want to!
Thank you, Telltale!