It is important to always keep in mind that societal progress is an unstoppable historical force. Setbacks of years, decades or even centuries don't matter in the grand scheme of things. Class struggle will progress as it always has since the beginning of post-tribal civilization. As the leading force of history, it will eventually sweep aside capitalism as it has done with feudalism, mercantilism and other modes of production before that.
This can only end in two ways at the injunction we are currently at: the continuation of exploitative modes of production - like capitalism and it's various derivatives - destroying the ecological base of our existence, causing us to tip over the point of no return of ecological collapse or the distruction of the exploiter classes, including their tools, and the construction of a socialist society with the goal of reaching communism.

So let us work towards making sure that the latter will come to fruition!

Setbacks of years, decades or even centuries don't matter in the grand scheme of things.

Yes they do. Imagine what could happen to certain society groups in the meantime. The whole nationalities and other groups could be exterminated.