I think we should start basing how good Mario is at being a bro based on which spin off game were talking about, because all Mario and Luigi’s are not born equal, for example:
Paper Mario: Worst bro. Holy shit someone help paper Luigi the man needs some love stat and paper Mario give about as many fucks for his brother as he has a 3rd dimension. 0/10 you didn’t even try to bro.
Main series 3D Mario: This is the Mario and Luigi that shows up in 3D World/ Land, New Super Mario Bros ect. They are the neutral bros, with Mario taking his brother with him on adventures and them helping each other out. A lack of characterisation makes it hard to tell how good a bro team they really are. 4/10. Would be 5/10 but there’s that one scene were Peach and Mario take off in a hot air balloon without Luigi, making him fall over.
Mario & Luigi series: Good bros!!! Best bros!!! This whole series is literally based around how much they work well as a team, There are moments where Luigi gets the short end of the stick but it’s balanced out by Mario hugging, standing by and helping out his bro. This Mario goes on long exhausting fetch quests for his bro and hugs him when he cries. These two would kick all their other incarnations asses. 9/10, because there is always room for bro improvement.