Zizek's point is that perhaps capitalism can't be fixed. Framing political and developmental issues using capitalist concepts and rhetoric may not only be contingently wrong, it's possible it's inherently, objectively and absolutely wrong.
Capitalism also = some element of plutocracy, even if it's held in check.
You can have competitive social Darwinism without capitalism, and it can even look socialist. All you need is some significant signifier of competitive success and severe consequences for the losers.
In capitalism, the signifiers are financial. (Although in fact that's just another form of totemic symbolism, rather than the objective status marker it pretends to be; persuasive individuals can manipulate this fact for personal gain.)
In other systems, markers can be social, historical, intellectual, or symbolic in other ways.
Market socialism - socialism which accepts that the economy must be industrialised, centralised, managed and monitored - is really just a softer variant of capitalism in which competition is constrained so that the consequences of competitive failure are less severe than usual.
It doesn't challenge the premise that competition is inherently good at all times, or the most effective way to improve the common good.
What seems to happen in socialised economies is that high taxation is collected, redistributed and invested rather apologetically, rather than being framed as - say - the natural and inevitable cost of participation in a beneficial social project, with built-in synergies of mutual advantage that are only possible when cooperation and altruism are significant social goals.
Again, capitalism without capital or capitalists. Unless by 'plutocrats' you mean the 'capitalists'. En un viejo país ineficiente, algo así como España entre dos guerras civiles, poseer una casa y poca hacienda y memoria ninguna. -- Gil de Biedma
Braudel's argument was that market economies have existed worldwide well before the rise of industrial capitalism and that, in essence, the marx/engels timeline was based on false extrapolation from an oversimplified view of a small period of european history.
That describes an unexpectedly small number of cultures.
It may not even describe this one.
