Who said it needed to happen without a fight?

The world where humanity ends without a fight due to capitalism "winning"...

All the rich people become bankrupt or otherwise loose their political capital, new politicians are elected in that owe more to workers and thus enact anti-capitalist policy to win over the loyalty of workers.

That or, as rich people loose more and more of their political capital, workers get empowered and use direct action (such as strikes) to demand the end of more and more capitalistic policies, until there are none left. The rich get along with it because the alternative is loose everything.

Or capitalism ends in a big messy fight.

It will happen. Communism ended without a fight.

Edit: And today's industrial society is quite far from being capitalist. Feudalism is more close to reality, seeing as the one most important factor for almost everything in life is whether you own real estate or not.