I think there has been moral progress, likely from the continued pressure of people trying to enforce their moral preferences, but there have been regressions as well, and there is nothing inevitable about it.

For example, I think Orwell's vision is horrifying because it seems plausible - just as under one set of conditions, it's like there's a benevolent invisible hand, under some other conditions, it would be like there's a malevolent fist. Whether you agree with Orwell or Hayek about what those conditions are, a morality death spiral seems a plausible proposition.