By not taking the opportunity during Covid-19 lockdown to merge iMessage & Facetime into one powerful communication app and making it cross platform, Apple may have missed out on its biggest opportunity to beat Whatsapp, Zoom and Microsoft Teams.
If I have to pin point a single factor that made Amazon and Apple a Trillion Dollar company its their impeccable, great to a fault 'customer service'! Many companies have great products, however not all of them are great at customer service, which is why they wont succeed in the long run.
Apple plans to release a weird combination of 3 or 4 iPhones in 2018. A minor change can make a huge difference in sales.