I find it somewhat plausible that this could actually lead to something like the show depicts. There is precedent for sweeping moral changes in human history. For example, large parts of the world now find practices like torture, slavery, and collective punishment to be repugnant. Those practices still happen to some extent, but they're not viewed as being just normal like they generally were seen back in the day.
Another example is how Europe and Japan after WW2 genuinely became more pacifistic. Not just as a pretense to fool outsiders, but as a genuine change in how the inhabitants see things.
Picard says at one point "A lot has changed in three hundred years. People are no longer obsessed with the accumulation of 'things'. We have eliminated hunger, want, the need for possessions."
At another point he says "The acquisition of wealth is no longer the driving force in our lives. We work to better ourselves and the rest of humanity."
To be fair, capitalism is mainly a system of contracts and laws that allow for certain kinds of ownership structures and investments. It does not necessarily have to be done in a way that is obsessed with the accumulation of things or wealth. So those quotes are also not really anti-capitalist. But the quotes are, at least, not friendly to today's common notion of what 'capitalism' means.