When I first updated my iPhone to Apple's iOS 12.0, I was frustrated that I couldn't rotate my iPhone to horizontal mode to get the bigger stock chart on Apple's native Stocks app where I could (previously) change the time range for the stock chart to 5 and 10 years.
Then I realized, though rotating your phone will no longer get you a full screen chart, the 10 year chart is its still available... you simply have to swipe left on the time range bar.
Swiping left on the iPhone stocks app time range bar will reveal the 10 year chart option as well as a new "ALL" option.