Seriously, EU should make some legislation against this kind of shady shit. It's confusing the consumer. If you don't want to make headphones anymore stop making them. Or license the "technology" but make them say "Sonova headphones with Sennheiser technology"
Same logic after reading and accepting the comments above.
1. A competitor offers an alternative product at a better price. 2. Sennheiser produces these more efficiently than anyone. 3. All alternatives have similar margins. 4. No other manufacturer has a similar product.
Whatever the case may be, it will inform the rational comparison shopping process. This is a discretionary item. There's probably some economics name for this, but it's not insulin. Sennheiser isn't coercing anyone.