Apple's AI assistant Siri, once revolutionary in 2011, is now lagging behind competitors in advanced AI features.Improvements to Siri have been delayed until 2026, raising concerns about its fall from grace.Apple CEO Tim Cook removed AI head John Giannandrea from overseeing Siri, appointing Mike Rockwell as the new leader.A fear of imperfection and a cautious approach to revamping Siri are seen as hampering its progress.