Windows Phone.
Microsoft · Steve Ballmer, Stephen Elop · Technology
A well-reviewed mobile OS that arrived after the app ecosystem had already chosen sides.
$0
spent
6 yrs 11 mo
2010–2017
Technology Obsolescence
Outrun by what came next
$7.6B written off.
TLDR
Windows Phone shipped in late 2010 with a genuinely distinctive interface — live tiles, typographic layouts — and consistently good hardware reviews, later reinforced by the acquisition of Nokia's devices business.
By then iOS and Android had the developers, and developers had the users. Third-party apps arrived late, thinly, or never; each gap made the platform less attractive to the next developer. Microsoft wrote off $7.6 billion on the Nokia acquisition in 2015 and confirmed in 2017 that new features and hardware were finished.
Windows Phone did not lose on quality. It lost a network-effects race that had already been run.
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