Hey, now we can compare the end of their careers.
Amla
Sadly played 12 continous innings against Australia and averaged 19, all played in very pace friendly conditions, managed two good fifties on spicy wickets against Pakistan and averaged 52 against them. Looked hopeless against the Sri Lankan pacers and decided to retire from Cricket. Average fell 6.14 points in approximately four years.
Harvey
Got owned by Hall and Worrell, averaged 17 in 8 innings, made a hundred at Edgbaston against Trueman/Statham/Allen, made 73 and 53 in spicy conditions during Trueman's game against Fred/Jackson/Lock where no other aussie bat performed well, made a great hundred coming in at 16-2 against Trueman/Statham at Adeliade, another decent fifty. Average went down 13 points in 6 or so years.
Kohli
Went away on his back due to Scott Boland, made a hundred but completely failed in rest of the series in spicier conditions, performed well on very spicy wickets in South Africa. Average fell by 8 points in a around 5 years.