There will always be poor and wealthy people and many in-between.
The problem with the current assignment of merit is that it is not correlated to the evolutionary value to humanity. The wealthy get rich over the backs of others, usually from some ingenious and opaque ploy to deceive others, and the poor stay poor, enslaved by the wealthy. Limited mobility is present because the oligarchic systems we built are by design resistant to renewal that would reevaluate their merit.
So, in essence, humanity has not evolved much since the Stone Age. The difference is that now we have legitimized some of the rules by which we pillage and plunder — not great progress for a species aiming to outlive a common fly.
Hence, we must reinvent the operating-system for humanity. To deploy a new thesis that determines what humanity can discover (Einstein). There will still be outliers on either side of the standard deviation of merit, poor and wealthy. But their status will be directly related to how they contribute to the strengthening of humanity to serve us all.