I might be wrong but in the case of Apple it seems that to its customers it's Apple that matters, not apps. It's a brand many people want to buy because of the same mechanisms that make people buy luxury brands. The only time I remember when Apple's branding wasn't really enough has been in the 90s when graphic designers left Macs for Windows machines because Adobe software run so much better there. It was an undeniable combination of hw and sw problems. All of them came back and more thanks to the iPod first and the iPhone later.

So you might be right that too many inconveniences will send faithful customers away (I gave an example) but I don't believe commoditized apps are such a problem. People buy Apple because it's Apple and only a barren app store could drive them away now.