Correct me if I am wrong, but I was under impression that Porche lost the bid to build Tigers, though? And all the chassis they built for it were instead used for the Ferdinand.
Nah wiki says your right. A company called Henschel made the tiger. Krupp helped with the tiger 2. Porsche was barley involved. I didn't even know he competed for the contract, I thought he just coined the name.
Because they were prohibitively expensive in materials to make. They were diesel electric. Like modern trains. But all the copper needed made them unfeasible.
From the World of Tanks wiki page for the Tiger P (Porsche variant), so take this with a grain of salt, but:
On May 26, 1941, Adolf Hitler ordered Ferdinand Porsche and the Henschel company to develop prototypes of a new heavy tank. The prototypes were shown to the Führer on April 20, 1942. Manufacturing began, but the production run was cut short due to the complexity of the tank's drive and control systems, and a shortage of the required copper. Later, 90 produced hulls were converted into Ferdinand tank destroyers.