The key to Apple's demise: iTunes is awful. Truly, truly awful.
That's one syllable long of a haiku. It also contains a bigger truth.
iTunes used to be about making an easy way for people to use their iPods. Then it became an easy way for people to buy music from Apple. Then it became an easy way for people to buy music and movies from Apple. Then it became the only way you could sync your iPhone. Then it became the only way you could manage your media. Then it became the hostage-taker of your media by a company that decided fuck you, you own a U2 album.
Acrobat Reader is this awful thing because it's a giant application with a CAD engine, a media embedder, a full-featured mail server and god knows what else that makes it so that the people who use Creative Suite can rest assured that their customers can view content as intended. But iTunes serves no master but Apple. It's horrendous middleware that exists solely to lock Apple users into the ecosystem. Much like iChat or Facetime or whatever the fuck they're calling their ad-hoc five-protocols half-proprietary clusterfuck of messaging tech these days - Apple could have come up with an open protocol that did all that shit and catch Google and Facebook completely flat-footed. But they didn't, they haven't, and they won't because siloing is far more important to them. I think Apple let iTunes become such a heinous chunk of shit because they recognized the future of media wasn't ownership, it was RMR and if all you're doing with iTunes is streaming their shit, it's acceptably bad. No worse than Spotify, surely.
This corrosion is hitting Google, too - Android used to be dope, but it's steadily turning to shit, too. Having experienced the clusterfuck that is Google hardware support, they don't give a fuck. Even when you are the customer, rather than whoever they're selling your eyeballs to, they give zero shits about your customer satisfaction.
Microsoft, I believe, understand that they're in danger of being left behind because of their calcified, prehistoric approach to business and engineering... but they're still putting that calcified, prehistoric approach front and center.
Amazon? Amazon hath become Walmart. They are the Walmart of the liberal elite, the guys who browse People of Walmart while shipping Sahale Snacks to themselves via Amazon Fresh. They are every bit as vulnerable to disruption as Walmart is. Their business model relies solely on monopoly pinch points.
Alibaba is on the blockchain.