The global smartphone market in 2022 was ~$500B. Is that big enough for you--or for Apple? It apparently pales in comparison to apparel, after all. One's position in one market can also leverage one's position in a related market. For instance, gaming and computing.
Except you're comparing Apples and, well, oranges... Apple built the smartphone market before it existed in part by leveraging another ecosystem it had already built (music/entertainment), not by chasing an ecosystem they weren't dominant in (gaming). By 2007, digital downloads were more than a quarter of just US sales, and the CD was in decline, and Apple was already the dominant player in that market.
Apple didn't hire Ron Johnson from Target on a whim... they wanted to build a retail presence. Tim Cook is from supply chain. The pieces are there to directly target Amazon at a point when their online presence is hampered by an un-navigable mess of knockoff, third rate products, and malls are all but dead.
There's more intellectual capital at Apple to topple Amazon. There's no point in wasting time with gaming when even the existing VR market doesn't represent much of gaming... so that $15 billion I cited is even smaller when you consider that's of the TOTAL gaming market, which VR hasn't captured.
VR user penetration is 1.3%... so cut that $15 billion to $195 million, which Apple makes in five hours. The development costs of the MR ecosystem are larger than what VR pulls in from gaming in a year across ALL manufacturers and software distributors.
There's a concept called Total Addressable Market... that $15 billion represents TAM. The total POSSIBLE market Apple could capture given the projected share of the $280 billion market they could plausibly convert. If the most they stand to gain is $15 billion if every single gamer on the planet goes to VR (which is not happening, ever), that's pathetic.
If the entire world market for VR gaming is $3.64 billion (1.3% of $280 billion) that tells you something about the prospects since VR has been around for a decade. In ten years, downloading/streaming grew from 0 to two thirds of the music market.