I could be wrong, but my impression is that Tim Cook is trying to position Apple as a lifestyle/fashion brand that happens to do consumer electronics and maybe a bit of software, and not as a consumer technology company that happens to be so cool it became a lifestyle/fashion brand by default.
His idea of better seems to be all about size and superficial design, not user satisfaction. Which would be good if size was all about the user experience - but it's not.
Jobs fucked up regularly (who remembers OS X 1.0?) but he still had a laser-like focus on the overall experience and he could rely on that to keep Apple on track.
Cook doesn't have that, and it's not clear that anyone else at Apple does. He's had five years of significant product launches now, and most of them have been okay-I-guess sidesteps - smaller, thinner, bigger, a different colour - or outright duds.
Also, U2.
Opportunities have been missed. Apple could have opened and owned whole new markets - user generated music and video, health devices, home automation, the power user high-end. Instead we got a watch and a a TV hardly anyone cares about, the promise of a car that will probably be late to the party, a music streaming service that streams music just like all the music streaming services do, and AI something something something maybe one day.
The money may still be flowing in, but the stock is going to get hammered if nothing changes soon.