“Apple will decline in the post Steve Jobs era,” writes Forrester Research Chairman and CEO George Colony in a new blog post provocatively entitled “Apple = Sony.”

While Apple continues to report record earnings, “Apple’s momentum will carry it for 24-48 months,” writes Colony. “But without the arrival of a new charismatic leader it will move from being a great company to being a good company, with a commensurate step down in revenue growth and product innovation. Like Sony (post Morita), Polaroid (post Land), Apple circa 1985 (post Jobs), and Disney (in the 20 years post Walt Disney), Apple will coast, and then decelerate.”

Read more of Colony’s analysis in his blog post.