Actually used 2010 cause otherwise i would have to type "2013 before richie left".

Mental reasons of why he started sounding worse instantly after Richie left.

Now if he's unable to hit C5 thats probably physical.

The reason he sounds better 2018 than 2017
is cause those bad mental stuff are going away.

Physical improvements to his voice wont come.
Mental stuff that he is getting rid of is slowly making him sound like what he actually sounds like when singing
(For example SIBSN Sao Paulo 2017 acoustic intro before song starts as example. Or Jon singing during karaoke bar prank.).