Yeah, it only took Juve 3 years of imploding their squad to play Ronaldo ball, alienating all the forwards in the team to focus their offense on him and lose Serie A after a 9 year winning streak, so you could come here to celebrate that Ronaldo beat Quagliarella, Immobile, Muriel and Lukaku for the top scorer trophy. Do you write for The Sun?
Messi is having some off months for obvious reasons, he's not fit, he probably had problems settling in Paris, a different league, new role in a team that has other players to share the burden of scoring goals like when his output plummeted in 2016 with Luis Suarez being on fire or even the fact that he has already hit the post 5 times in 12 games. There's a mix of logical reasons and also abnormalities that probably explain his performances.
If you want to compare his first season outside of Barcelona to that other 5 time Ballon d'Or winner, you may also be able to remember that on his first season a Juventus his overall scoring output was almost a half of his last season in Real Madrid, so Messi not being at the level he had in Barcelona these past months it's not something to write home about, more than expected.