Would Marxism create...?

I think what people often miss with that argument though is that, even allowing for the atrocities and major mistakes committed by the socialist regimes, the majority of the population were better off than what came before. Tsarist Russia was not known for providing for its citizens, giving them political power or caring about their human rights. Nor was Cuba under Batista, Indochina under the French, China under the emperors or the Japanese etc. In all these cases there were increases in the general welfare of the populace following their revolutions. And those that reverted to capitalism often saw a rollback in that welfare.

Another point is that many of the problems of these regimes were often more due to hostility from the capitalist world than internal issues - the Russian Civil War would have been a lot less bloody if armies of foreign countries hadn't invaded to support the much smaller White Army; Cuba and N Korea would be wealthier without the economic sanctions placed on them etc.

Finally, on an international scale, capitalist powers have been involved in mass murder, human rights abuses etc in order to protect and increase profits eg supporting Pinochet in Chile. And even at a domestic level there are obvious problems - homelessness, high crime rates, and the US prison system compares poorly to CIA reports on the Soviet gulags in the 50s.

Of course, all that doesn't mean socialism doesn't have its dangers but we should acknowledge these without simply conceding capitalism is the lesser of two evils when it is in many ways as bad or worse.

The problem with that is under capitalism, you have massive wealth differences and those with vast wealth can use that resource to sabotage any attempt to regulate capitalism.

However, even if there were some way to make capitalism fairer, it's still a system that's based on people generating more wealth than they are rewarded with. It's still a system where profits will inevitably tend to decline, leading either to collapse or pursuing more immoral forms of growth.