No, you want a share price as low as possible for share buybacks. As long as the price doesn't get bloated the waters are clear.
[Remember, the objective of stock buybacks is to buy back shares on the open market and retire them, increasing the % ownership of each shareholder (and thereby the intrinsic value of the security) correspondingly].
[[Or you can view it as the company holding the shares for the shareholders, mathematically it's the same]]
They have the cash and people generally invest in AAPL for reasons other than having a stake in a bond fund, so it makes some sense. Buybacks vs special dividend are debatable, but impossible to say what is better until you see the future share price. They did hike the dividend substantially too so they're playing both angles.
No, it will decrease the amount of money they have to pay out in dividends though... Theoretically the yield would decrease since the share price should increase as shares are bought back. That said, they did also announce a dividend increase which should counteract that.
Think about it in round numbers, if there are 1 billion shares and a $1 dividend it's $1bn per dividend payment. If they buy back 100m shares, the next dividend payment would be $900m.
tl;dr dividends are declared on a per share basis, not a total amount that is divided by the current number of shares.
[Remember, the objective of stock buybacks is to buy back shares on the open market and retire them, increasing the % ownership of each shareholder (and thereby the intrinsic value of the security) correspondingly].
[[Or you can view it as the company holding the shares for the shareholders, mathematically it's the same]]