It was said in jest (kind of!), but if we are going to talk share prices, the recent significant AAPL drop in share price reflects the overall market drop over that period, albeit with greater volatility typical of AAPL long term. Over the period of your graph (2 years), AAPL has increased 35%, whereas the XLF (Technology ETF - basically representative of the tech sector as a whole) increased only 13%, and the DOW only 2%. The NASDAQ (on which it is listed) increased 17%. AAPL has always been more volatile, and it's drop from the mid July highs has been 22%, compared to 7% for the XLF, but even accounting for that has outperformed both it's sector and the market. As to market share, 40% is pretty impressive in anyones books. I don't have data on % increase or decrease in market share to comment on though. TSLA over that period has had quite a ride and is currently about 10% up on where it was two years ago (but, I think, with a lot of upside potential if they can nail the model 3 release and production schedule).
Pontificating on the past like I have just done anyone can do... now if we could REALLY predict the future I would enter my order right now for a fully optioned up P85DL and a Model X and give my 85D to one of my kids