How does that make a boss feel if an underling is making significantly more? What about Luciano, Genovese, Gambino etc., as old time bosses were soldiers making more than them? I would imagine that they would start to question why they are not making the most in their family as they sit at the head of the table.
I doubt that there would have been that much of an issue as long as the money kept flowing up to them. Look at the Chin, he was as old school as they come and he was ok with all of Papa Smurf's success. Also as to Genovese himself, Jerry Catena, his underboss, made more than he did and he was ok with it as long as he got a piece, he even made him acting when he went to prison. Money is only part of the equation, for many guys the power of being boss is the most important part of the position.
