This is exactly it. I fly to India. SEA to FRA to India is the general route. Lufthansa has the shortest flight times including the layover in Frankfurt.
Every other airline takes at least a couple of hours more. Some take 4+ hours longer.
This seems impossible. Frankfurt is nowhere near the great circle route (shortest path) between Seattle and India, and Qatar flies directly from Seattle to Doha, which is near the route, and which itself has frequent direct flights to many airports in India.
And indeed, a quick flight search shows that Qatar's total flight times from Seattle to major Indian airports are all at least 2 hours shorter than Lufthansa's.
Every other airline takes at least a couple of hours more. Some take 4+ hours longer.