Reason :-
Very less movies .Even they are not mind blowing either .
Limited actor ...can not do comedy
Sex appeal less ,because now a days he looks girly
Ageing
His forte dancing ...but does not do or try any new form ..
Off screen personality ..dull ... he seems too conscious
Got married in very early
No PR
But
In last 15 years if any actor could successfully be in No 1 position apart from Khans it is HR
Looks better than all three of them
Dances better than them
At least 10 years younger than Khans .Even after doing 1 film in 2 years ..Still in top 5 ..He is mostly in 4th position ..Not a bad position at all