Umm no, share holders and the board definitely has a voice and I think we are not too far away from Tim leaving as CEO. Normally they'd give a guy like this a year maybe 18 months to right the ship, the only reason why it would be longer at Apple is because their development and release cycle is absurdly long. If it takes 3+ years to upgrade each product line, he might get 3 more years at the helm before they politely oust him.
For share holders, the pressure on Tim Cook is not for him to step down. The pressure on Tim Cook by many share holders is to focus only on iPhone and for him to abandon the Mac, Apple TV, and other things that are not considered material to the profits of the company.
We saw this before during the iPod domination years. Vocal share holders wanted Steve Jobs to ditch the Mac and focus only on iPod.
How did you come to this conclusion? I've been using Apple computers since the late 80s and iPhones since the day the 3G shipped in 2008 and consider Apple's current computers, phones and accessories to be robust, of the highest material and design quality, and packed with cool tech. I walk around with my 7 Plus feeling like I'm a goddamned cyborg. I look around the streets and see a significant number of people sporting an Apple Watch while I've seen next to no one wearing a competing smart watch apart from Fitbit...which is pushing the definition somewhat. Around Christmas I was surprised to see quite a few people with AirPods but have yet to see anyone with another brand of wireless in-ear headphones.
You know what Tim isn't very good at? Being a bullshitter/salesman the way Steve Jobs was. And to sell the company to people who can't objectively see that Apple is doing some very cool things.