SAN FRANCISCO, United States — Apple celebrates its 50th anniversary as artificial intelligence (AI) 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. The Apple logo is pictured on a large digital screen at the start of...