I'm sorry, but no. "Fixing" a useless statistic feature that most people don't even bother with is not worth the immense gold drain that these "top families" would cause in their realms if they had the opportunity to accumulate more near-useless family wealth.
Is gold draining really a problem? If you want to drain gold for the sake of your own family 'status', why not? If that leaves the realm with too little reserves to win a war, you probably made the wrong decision. Real history is full with accounts of great useless expenditures of kings and lords that bankrupted their realm, land, duchy or barony. While it isn't possible to go bankrupt in Battlemaster, I think making family wealth limitless will make gold circulating in-game more scarce. Which is interesting for war.
About gold in general, the fact that everyone is just giving it away for the 'benefit of the realm' is also not very historically correct. In real life it has more value, which creates more intrigue around it. I think it would be an interesting discussion how we can increase the value of gold, to make people want to go to war over it.
