They do already, integrated into products/devices that need them. They're certainly not going to make separate/discrete DAC or amplifiers. In terms of audio, Apple is on a roll with spatial audio.
btw, What Apple is doing now/next (and it does relate to AV) is...
Apple Rumored to Announce 'Game-Changer' AR/VR Headset in January 2023
Kuo said that the device is "the most complicated product Apple has ever designed," leading Apple to use components from many of its existing suppliers. Kuo also believes that Apple will be an industry leader in the headset space, has "significant competitive advantages," and does not need to join the Metaverse Standards Forum. Notably, Kuo thinks that rivals will race to imitate Apple's headset once it launches, "leading the headset hardware industry to the next stage of rapid growth."
" I know there are a lot of naysayers for this product but this is a potential iPhone moment. A see it to believe it product. Apple's big product intros tend to be 10 years in the making. The concept has been around for a long time but nobody has done it quite right. The weight of the headset, the miniaturisation of optical components, Apple's processor advances, software and tools development via iOS and so many factors play in to this having transformative potential. "
" It really looks like a very slow game of chess. They have been developing tech (see: LIDARs, AR, SOCs) sometimes with modest short term gains, and everything looks like converging now into a grandmaster checkmate. "