Preventing concentration of wealth can only be valuable if it leads to a more equitable system. Otherwise it would have the same moral weight as preventing oversized dirt clods.

Preventing concentration of wealth is more valuable than preventing oversized dirt clods. It prevents concentration of power.

... thereby leading to a more equitable system, right?

If not for more equitable society, what's wrong with concentration of wealth?

Wealth begets power. We have checks in place for political power (term limits, separate branches of government). We have restrictions on arms (tanks, anti-aircraft guns).

Lots of hand wavy things and also the presumption that wealth must have come at some undue cost to others (eg low wages)