Take Sony as an example. Buying Sony meant you were getting a good product. Now it doesn't: generally you have to buy the premium end, or at/and know exactly what you are looking for.
Apple earphones are another example: very bad quality.
Brand loyalty died already.
Brands are good enough for most people. Also, I think there's some natural law against declaring brand loyalty dead immediately after mentioning Apple.
I know no Apple fan that buys Apple earphones.
It's easy nowadays to look up the Amazon reviews instead of just buying something with Harman Kardon on the side, but people still shell out tons of money for Prada shoes. (I think this partially applies to Apple, but not completely because apple products tend to have a large user experience advantage.)