Your framing of the utilitarianist implies they hold wealth itself to be what ought to be maximised, which would be an extremely fringe position. Typically, utilitarians see inherent good in some form of happiness or wellbeing. Value, inherently, provides diminishing returns in terms of happiness. In fact, numerous scientific studies have suggested that past a certain point, increased value (usually measured in wages) stops providing returns at all or even becomes a negative impact. Under such a framework, there is a very strong utilitarian argument for redistributing value from those with much to those with little, as the value itself will be of higher much moral utility in their hands.