ThisPretty much any character with a KG has had their powers given to them genetically, Sasuke is no different, all of the Uchiha are no different. Let us just say that his road to power is more emotionally trying than physically trying.
Look at this way. The sharingan can copy any non KG move. Correct?
To gain the tomoes of the sharingan the Uchiha must be put into dire, stressful situations. Correct?
To gain MS they must witness the death of their closest friend. Correct?
To gain EMS, they must take and implant their brother's eyes. correct?
They're not gonna get it punching a tree 1,000 times, they're not gonna get it practicing over and over and over again.