It's not for the reason you're probably assuming.
First thing's first: the BMW 3 Series Gran Turismo is a bit odd-looking. That's not to say it's not a good vehicle because it is. It blends nearly everything we love about the previous-generation 3 Series sedan with additional interior space and slightly raised seating position similar to that of a crossover. For BMW shoppers who still preferred a sedan over a crossover but interior space remained an issue, the 3 Series Gran Turismo offered a solution. As we already knew, however, BMW opted not to offer a direct successor of the GT with the latest generation 3 Series, but the automaker's reasoning is probably not what you think.
According to Autocar, 3 Series Gran Turismo production has officially ended. It is also no longer being advertised on the official BMW website.
This hatchback-like 3 Series was first launched back in 2013 and updated for 2016. Despite its interesting exterior design, it was not anywhere near as ugly as the also discontinued 5 Series Gran Turismo, which left the lineup in 2017 but has since been replaced by the more conventionally styled 6 Series Gran Turismo. However, BMW did not discontinue the 3 Series GT solely because of its looks, but rather due to cost-cutting measures initially ordered by now-former BMW CEO Harald Krueger. The ultimate goal is to save over $13 billion.
Although BMW does not provide a precise sales breakdown of 3 Series GT versus the sedan, it can be fairly assumed the former did not achieve anywhere near the same level of success as the iconic sedan.
The 3 GT was definitely more of a niche player that was increasingly having a difficult time justifying itself in a crossover-dominated world. Additional cost-saving measures BMW is putting into place include reducing nearly half of its current drivetrain variants by 2021, which will be made possible by the shift to just two flexible platforms. This will make future vehicles less complex and reduce development time.
The BMW 3 Series Gran Turismo was not by any means a bad vehicle. Sure, its styling wasn't for everyone but BMW simply could not justify the costs to launch a successor.