Number one is very hyped IMHO. Take rafa before this year's FO. He won 3 out of the 4 last GS, the olympics and many masters. He was on fire.
An early loose in FO and everybody is counting that roger can get back number 1 after wimby. ATP scoring system is very demanding, and a bad strike puts the number 1 back to 2 quickly.
I don't agree with many players who asked to extend the scoring system across 2 years instead of yearly because that's the way it's been until now and because it makes something extraordinary to keep #1 for a long time, but it's also "easy" to become the #1 even if it's just for a few weeks.