Since then there's been a realization that you can simply regulate the worst aspects of capitalism while still reaping most of its rewards.

Now, that has been realized - but hasn't happened - in the United States, but it can certainly be done.

It'll probably be too late though.

So what? People have been misinterpreting and misusing knowledge, realizations, and stories since basically forever. That doesn't make the original works worthless or any less insightful. You would be hard pressed to link most of the policies of communist nations to things Marx said or advocated for. The vast majority of Marx's works is pointing out flaws in capitalism, not prescribing policies to use instead.