Sales or stock prices doesn't mean a product is good.
Look at Microsoft in the mid 90s. Was Windows 95 really that good? Not really, but it was the best thing (the only thing?) at the time. They marketed it well and it sold.
A lot of people are invested in the Apple ecosystem dating back to the Steve Jobs era. I'm one of them. They can either plow through or go back to Windows. Apple despite the short-comings (product neglect, sloppy programming, bad MBP keyboards) is still better than going back to Windows (although I admit the has closed quite a bit).
AirPod are good. But really, they do fall short in a few areas. Despite any shortcomings a lot of iPhone/Mac users are going to buy them over another brand because it fits into their existing ecosystem. Unless there's a huge design flaw, they will be a hit regardless.
High stock prices also doesn't mean Apple is better than ever. Stock prices are a result of public perception of the company. We all know Apple is genius when it comes to marketing. Proof of this can be found with today's article:
https://www.macrumors.com/2018/05/07/aapl-all-time-high-above-187/