He didn't earn that shyt.He probably just whined and cried to splinter so much about it like a little ho the rest of the turtles were like "whatever man it's really not that important,you can have it "
You buggin breh, none of what you said happened in any incarnation of the comics, movies or cartoon unless you are talking some new shyt post 2011, which I'd say "how old are you?"
Leo was THE most hardworking and disciplined turtle there is, Splinter put that faith in him because he was the only one that could consistently produce.