Why did Olivia Newton-John and Elton John quit singing together?

Olivia Newton-John and Elton John have not formally "quit" singing together, but their collaborative performances have decreased over the years due to their individual careers and personal commitments. Both artists have pursued solo projects, with Elton John focusing on his farewell tour and Olivia managing her health challenges. Their occasional duets and collaborations remain cherished, but they have not maintained a consistent partnership in recent years.