The graphic UI and the case design were distinctive. But what really sold it was an incredibly sophisticated ad campaign that carpet bombed key media outlets with super-expensive exposure.
The problem with Symbian/Blackberry/Palm wasn't just mediocre technology, but a lack of dazzle. The products were functional but mediocre. But they were also marketed in mediocre geeky/corporate ways that just weren't that interesting to most consumers.
The original iPhone was barely more functional. But again, exterior aesthetics and a huge marketing and PR campaign forced open a consumer market for a product that was - like the original Mac - barely finished.
The problem Google has is that its products and its branding are heading rapidly towards mediocrity. It reminds me of DEC - an engineering giant in the 70s and 80s, which forgot how to read the market and innovate in the 90s, and crashed far more quickly than anyone would have predicted.
That's the reason that Apple, especially, has been so successful. It's not because they launched at some perfect time window. It's because they launched damn good products. If the iPhone had launched in 2008, or even 2009, it would have been just as successful. We just would have had another two years of mediocre Windows Mobile/Symbian OS/Blackberry devices.
[1]: https://www.folklore.org/StoryView.py?project=Macintosh&stor...