Thanks a lot for the responses, I agree that giving the same salary to everyone is probably not a good idea, and you are right that if some one pay you higher it’s is because he estimate you provide him more value. Of course the interest of the one that pays you may not be correlated to the global interest but I better understand the logical at saying that the best effective way to do good can be to earn as much as we can in order to give more, and it doesn’t imply that what we do in our work is necessarily the best for the society in itself.
I am still not very comfortable at envisaging my self as a benevolent dictator, but I realise that until the society is not sharing effective altruism ideas in it’s almost totality, it is probably the most effective way. And to be honest I am currently far from giving enough (in percentage and quantity) to be risking to that anyway !!
I’m still have some psychological barrier with the idea of trying to earn always more but it is certainly linked to some anti-consumerism beliefs that doesn’t apply here as the goal is not to buy more useless things and services and given that there is probably too few effective altruists to have a impact on society, global salaries.
Moreover the impact of income inequality on happiness is probably lower that I was unconsciously thinking (https://www.pnas.org/content/107/38/16489), even if it may have also other negative impacts impact like confidence in the society.