Football is very much like Quantum Mechanics. The universe permits the footballer to use either his left foot or right foot as he sees fit. But occasionally an episode of "decoherence" occurs, when the universe enforces the specific use of either the left foot or the right foot.
Name one top player playing in Lamela's position as either of a winger or an i.nverted winger who, when an episode of decoherence occurs and the universe ordains the use of their weaker foot, that they are unable to produce a high quality cross or shot with their weaker foot.
I'm going to second guess you and say you'll name Robben, but you'd be wrong. View this video as evidence:
[video=youtube;ZzZkiHBOuH8]https://www.youtube.com/watch?v=ZzZkiHBOuH8[/video]
At 0.46, 1.13, 3.40 and 9.28 episodes of decoherence occur, and the universe enforces the use of his weaker foot, and because it was drilled into him at an early age, he was able to meet the universe's requirement.
Really, it should have been drilled into Lamela when he was a youth player and it may be too late now - it severely limits him as a footballer and is what will, in my opinion, make him fall short of ever being a truly top player.