You should see it as the triumph of chip manufacturing — advanced, powerful MCUs have became so cheap thanks to manufacturing capabilities and economies of scale means it is now cheaper to use a mass manufactured general purpose device that may take more material to manufacture than a simpler bespoke device that will be produced at low volumes.

You might be wondering "how on earth a more advanced chip can end up being cheaper." Well, it may surprise you but not all cost in manufacturing is material cost. If you have to design a bespoke chip for your earbuds, you need to now hire chip designers, you need to go through the whole design and testing process, you need to get someone to make your bespoke chip in smaller quantities which may easily end up more expensive than the more powerful mass manufactured chips, you will need to teach your programmers how to program on your new chip, and so on. The material savings (which are questionable — are you sure you can make your bespoke chip more efficiently than the mass manufactured ones?) are easily outweighed by business costs in other parts of the manufacturing process.