Sorry, but the "grumbling" you hear is totally irrelevant and speculation. Apple is a nearly $1T company. How could there not be grumbling? You're overrating small issues, extrapolating them, and ignoring facts.
Why wouldn't you wait until the numbers change to change your investment thesis? Every single person who has predicted the demise or even the slowdown of Apple has been straight up wrong.
Short answer, the Surface and other competitors don't use iOS ad Mac OS.
Forget all the sales numbers. They are stellar. Are you totally discounting that they are going to change AR/VR in a big way? Cars? Other stuff?
And the buyback. Oh, the buyback. I don't care if their sales don't grow at all. They are buying back $100B in stock, very quickly and make $55B in earnings annually.
The numbers speak for themselves. Sure, it can all change. It can slowdown. It can crash and burn. But you'll see it in the numbers. See their 2018 Q1 and Q2 reports? Breathtaking. Everything you're referencing sounds like someone reading too much MacRumors.
Dude, my cost basis is single digits. Chill out. I’m well aware of how well the company is performing. As for grumbling, you have to be willfully ignorant to ignore the grumbling and focus exclusively on the numbers. Mac sales are generally flat. I bring up Surface only as an illustration of innovation in the face of Apple’s stagnation. AR/VR is a whole lot of hot air right now. Cars? We’ll see. Apple has been near bankruptcy before. They’re not perfect.
Consumers are fickle. I’m sure Sony thought it was on top of the world back in the Walkman heyday. I’m sure Microsoft thought no one could ever challenge them. And then they completely blew it in the mobile space. Right now I’m happy with Apple as an investor and see no reason to divest. However I wouldn’t be cheering stock buybacks over growth. That’s a telltale sign that something is wrong. As a user, I see many problems. Buggy OSes. Crap products like HomePod. Allowing the Mac to wither on the vine. Zero innovation in the desktop space. I’d still rather use a Mac, but for how much longer? Apple keynotes used to be the most exciting game in town. Now they are these extruciating snoozefests, or worse, naked, cheesy pandering in an effort to look “cool”. Meanwhile, Google blows us away with compelling tech while Apple pumps services revenue as the next great thing. From where I’m sitting, Apple looks a lot like 90s Microsoft.