What is the relevance of Karl Marx’s theory?

Even after the collapse of the USSR, Karl Marx’s theory is still popular, albeit in much smaller quantities. Nevertheless, we can say that it has not lost its relevance, and there are several reasons for this. Firstly, until now, the structure of society has not been invented, which suited everyone and was considered ideal for everyone. So this is what you need to look for such a device. Secondly, his theory still seems to people to be very humane and humane, ideal and honest. Many people like her to this day.