It did start going down in about August of 2000 for the reasons above, but there was still periods of greatness in the months to come like Angle winning the title, WMX7, Austin heel turn, Austin/Angle skits, and the summer of Benoit and Jericho in 2001. The invasion was the first time you can look at where everything started falling apart and nothing seemed to go right. Some of it was still entertaining like Jericho as the world champion, and nothing that year was as bad as when HHH came back and took the life out of WWE in 2002. But the start was definitely the invasion, the middle of 2001.