These two world-class companies have generated strikingly similar investment returns over the past decade. Now, it's time to look forward.You'll struggle to find better consumer-facing companies than Apple (AAPL 0.07%) and Costco Wholesale (COST 0.23%).These two companies have built massive, loyal customer followings, and their stocks have delivered life-changing investment returns over the years on their way to becoming two of the world's largest companies by market cap.While both stocks may struggle to de ...