From the OR studies conducted at the time, it does indeed seem that crews often abandoned perfectly decent tanks under fire, especially from air attack. It was considered safer to be hiding in an inconspicuous ditch than being in a huge and obvious metal box packed with explosives and fuel.
Other times they just broke down or bogged with minor mechanical problems, the crews bailed and for whatever reason the vehicles weren’t recovered.
Reading the memoir ‘Panzer Gunner’ which covered the the 7th PzD on the Eastern front in 1944, it was striking as to how often the crews abandoned and blew up their (new) jagdpanzer IVs, due to what seemed to be fairly minor damage, eg a damaged gun mounting in an otherwise fully serviceable vehicle.
The Germans had problems recovering their heavier tanks, officially it took 2-3 Sdkfz 9 heavy half tracks to tow a single Tiger. (1-2 for a StuG IIRC).
Tiger crews were officially forbidden to tow other Tigers as it usually just led to the loss of both tanks due to transmission failure in the towing vehicle.
German tanks came prerigged with demolition charges to use if abandoned. And they did just run out of fuel, eg during the Battle of the Bulge, where many tanks were abandoned and blown up for just that reason.
That wasn’t the case earlier in the war, when the Germans were renowned for their efficient recovery techniques http://www.lonesentry.com/articles/ttt08/german-tank-maintenance-recovery.html http://forum.axishistory.com/viewtopic.php?t=213726 https://www.quora.com/How-did-the-Germans-recover-their-tanks-in-WW2 http://www.dupuyinstitute.org/ubb/Forum5/HTML/000024.html