Parties don't really represent interest of their voters. They fish for votes to obtain political power, but they represent the interests of the people who run them (and their friends and patrons) - who are, generally speaking, not their voters.
Thus, traditional parties represent the interest of some subset of the established elites. Which means that the current socioeconomic arrangement is broadly in their advantage. They know that those problems are real, but they can be only solved by giving up some part of the pie. And organizations are much more selfish than individuals, so they never give up unless they believe that the alternative is to lose even more (hence why a messy revolution somewhere else can often do wonders).
Thus, traditional parties represent the interest of some subset of the established elites. Which means that the current socioeconomic arrangement is broadly in their advantage. They know that those problems are real, but they can be only solved by giving up some part of the pie. And organizations are much more selfish than individuals, so they never give up unless they believe that the alternative is to lose even more (hence why a messy revolution somewhere else can often do wonders).