In a lot of cases, they have simply ceased to deserve it.
In years gone by, 'pillars of the community' were seen by their position and status as simply beyond bad behaviour, and the notion of reproach by their underlings.
Now, history shows that these people are not only as fallible as the rest of us, but that they take unfair advantage of their status to exploit and abuse people in their orbit.
Leon Brittain may yet be proven to have been an abuser, history will tell.
As for Prince Andrew (prince of the blood royal no less) - he may well be innocent of the charge against him, but his continuous and continued profligate attitude combined with his acknowledged boorish behaviour means that he does not enjoy the automatic rights perceived of his status and birth right.
Respect used to be automatic, conferred on the 'great and the good', but in modern times, it has to be earned, as indeed it should.