I think they've managed to do that for a couple of reasons. First, I think there was enough desire in leadership to prove out the platform that they designed and marketed the two cars as aggressively as possible in an effort to move units. Second, while there's a price point correlation just north of $100k, the Taycan is available in a much broader range of trims and performance specs - and thereby, price. It starts at just over $80k and can run as high as $185k. The e-Tron GT is a very narrow offering and costs right around $104k, with a very limited range of options.
The other thing to consider is that the MQB is an IC platform. Revising it for electrification would really give you a slightly modified MQB, it would be a completely different platform, altogether.