One way they lost was that they ran out of steel. When the British introduced the Tank the Germans knew they had to have this weapon but they only had enough steel stock to put together two machines.

There may have been more in the planning stages and more being tested, but all the records I can find list only two that were operational.

When the US showed up, with its' unlimited amount of production capacity, the Germans knew it was over for them. It was only a matter of when.