The year the hardware fixed the sound

The console shipped in 1983 and the audio was already fixed

The Famicom's launch froze the sound hardware for the console's whole life, so every later advance had to come from the cartridge or from the composer.

The audio was cheap because it had to be

The 2A03 puts the sound unit on the CPU die to save parts, and the compromises in it are a bill-of-materials decision before they are a musical one.

The sample channel cost more than it was worth

DPCM playback steals CPU cycles and cartridge space, so it was mostly spent on a kick and a snare rather than on melody.