Capitalists will clean the world if it profitable and well. Since it is becoming profitable to be clean many are doing so.
But capitalists could first get rich by not having to pay for polluting the environment, and by the time everyone else has to deal with the pollution they'll move somewhere else clean.
Oh true. Certain industries got rich before anyone clued into the damage, and will always work for ways around the rules. At least it has gotten better. The trend is positive at least.