Plat farmers have to earn the money the same way the rest of us do... they are not the cause of the ingame inflation.
The economic problems within DDO are purely created by Turbine by "printing" lots of money without having very many ways of spending that money.
They tried adding a few things here and there (e.g. cash for additional pack and bank slots, the insane AH cut) but there is just not enough to soak in the cash thats being created... much more needs to be done before the economy will ever come into balance.