You mean like how they executed with Siri. Siri was also supposed to define a market and take over the world. In the new iPhone there is no mention of Siri at all.
Siri hasn't gone anywhere and it's still being improved.
There's no mention of it anywhere? So what, there's many other previous headline features they're not highlighting.
I'm not implying that Apple can't make mistakes - it's clear they can with Maps and Siri - but a) it would be extremely uncharitable to judge them on version 1.0 of Maps and Siri, both ridiculously complex features, and most importantly b) their overall product strategy is still the best in the business. Doesn't matter how much people kick and scream about the newest Apple mistake - does anyone even remember Antennagate? Tech people cling to these memories, but normal people forgive and forget.
You have a good and reasonable argument, but I'd like to offer a couple of counterpoints.
1. In other contexts, the sheer perfection of their 1.0 products are exactly what Apple is judged so successful by. As with the commentary on the fingerprint scanner: the praise is that while other manufacturers deliver buggy, incomplete features, Apple gets things right on the first try.
2. While it's true that everyone makes mistakes, Siri and Maps were arguably the highest profile features on the 4S and the 5, respectively.
I don't think Siri falied, but disapointed. Apple hyped it up so much you would believe it could do anything, and work flawlessly. Instead it works halfway reasonably in a few soecific situations.
I can't recall the last time I used Siri on my iPhone, or anyone else I know, for that matter; however, I've used Google Now on an almost daily basis on my Nexus 7. Execution is key.
I think when parent(s) were remarking on execution mattering they were implying: 'Execution is key ... to the success of the feature (and consequently) the brand'. My experience is very few people know what Google Now is. Your preference of it does not demonstrate an example of that sort of success-due-to-execution that other posters are suggesting Apple's products exemplify.
Have there been recent instances of Apple cutting features from a device on a new release?
I hope touch id proves to be successful, but I'm really interested to see what happens if it's not. How do you save face and stop investing in a technology, while also weaving a story that convinces customers they don't need it anymore?