For an instance lets consider all four brothers lead the normal human life and no god avatar, and we take the brothers in pair, Ram-Lakshman and Bharat-Shatrughan. All the brothers were equally qualified in all fields, all were good in their behaviour, son of a mighty king and student of Guru Vashisth. So the equation was Ram-Lakshman = Bharat-Shatrughna
But it was not so, what was the difference between these two pairs? Why Ram-Lakshman was given much importance compared to Bharat-Shatrughna? Here I feel the major difference was the mentor in the life of Ram-Lakshman. Yes, its the guru Vishwamitra who made the difference and changed the equation as Ram-Lakshman > Bharat-Shatrughna
We have so many teachers from our childhood, but after your doctorate when anyone asks about your mentor, simply we mention our Ph.D supervisor only. There is a proverb which states "show me your friend, I will tell about you" but in reality its like "Show me your teacher, I will tell about you". The guru is the one who shapes your career. Ram found his life sita through guru vishwamitra. We may say, they are avatars if not vishwamitra then also they could have got married. If that is the case, what is the need for guru to intervene in their meeting? If we consider Ram as god in this context, then also it means god wants the guru to set the things straight.
It was a time when teachers chose the student depending on their ability, but now students chose their guide with just half-knowledge. I want to emphasize it with the words of Noble Laureate Sir C.V. Raman about Prof. G.N.Ramachandran. Sir C.V. Raman told the head of Elec. Eng. Dept, IISc to allow Ramachandran to join physics dept by saying " I am admitting Ramachandran into my dept as he is bit too bright to be in yours" - ref Raghupathy sharma in Ramachandran: A Biography of the Famous Indian Biophysicist (1998).
Now we just don't lack students like Ram-Lakshman but also teachers like Vishwamitra.
Note: This is just my POV and its not universal law. I welcome all healthy discussions. Our words shows who we are. So lets maintain our own dignity.