Apple celebrates its 50th anniversary as artificial intelligence challenges the Silicon Valley legend to prove it can deliver yet another culture-changing innovation.Steve Jobs, a driven marketing genius, and Steve Wozniak, who invented the Apple computer, revolutionized how people use technology in the internet age and built a company now worth more than $3.6 trillion.The two college dropouts changed the way people use computers, listen to music and communicate on the go, giving rise to lifestyles revolving around smartphone apps.Apple's hit products – the Mac, the iPhone, the Apple Watch and the iPad – command a cult-like following, long after the…