White players in search for the win are sometimes annoyed when people play the berlin defense against their ruy lopez. I notice that the italian game often reaches position very similar to the ruy lopez middle game. So my question is why grandmaster do not switch to the italian game as the new E4 main line?
In italian game black put his bishop easily to c5 while not making too many concessions. In Ruy-Lopez prospects of that piece are usually worse. Berlin is not the main choice for black in the first place and it isn't horrible to play with white either. Many black players just stop thinking about Berlin the first time they see Re1 line. No fun at all. Endgame, while interesting, also not to everyone's taste. And white can settle for d3 systems. Black positions seem perfect by machine eyes, but still people prefer a6. The more people play a6, the less you worry about Berlin. And you can still make your opponent suffer in Berlin.
I am not grandmaster, but I took lessons from one, and he said RL immediately threatens defender of center pawn, whereas GP is less aggressive (more quiet). If you want a sharper game the RL is sharper, but both lead to open games. I was told if opponent kicks pawn to take knight immediately.
I find that a lot of people don't like their knight gone right away. Others don't seem to care so much as they might keep the bishop pair. Some of chess is personal preference. Experience players will try to find games that their opponents have played, see what they do when they play black or white, and the prepare to give them the kind of game they don't like.
The Berlin defence only got popular after the world championship match in 2000. Various lines have been tried over the years to play for a win with white. So it is not like it made the Ruy Lopez immediately drawish.
Some possible answers to your question:
Some (older) grandmaster or coaches might still be more used to the Ruy Lopez than to the Italian game.
Even the Berlin is not automatically a draw but requires precise play.
The Italian does not give much of an advantage for white either. It is mostly played for trying something new, perhaps less analysed.
Some white players might like the Berlin endgame.
Some black players might not like the Berlin endgame. If white is aware of it, no need to forego the Ruy Lopez.
Overall most decent openings if analysed well enough will lead to drawish positions.
PS: Magnus Carlsen just won against Karjakin in the WC match in an anti-Berlin (not because of the opening though) and did not achieve much in the Italian.