Germany's largest automaker has recorded sliding profitability, with its China unit under pressure as demand for luxury automobiles wanes. Specifically, demand for its Porsche Taycan has run out of juice, leading to significant markdowns. Bloomberg Intelligence's Joel Levington published a note on Monday highlighting the bleak demand story for the Porsche Taycan, which has forced the struggling German automaker to offer markdowns of $22,500. Additionally, the vehicle's used value plummeted in 2024, while data from iSeeCars research finds…