You're claiming that if capitalism tends to backslide into X, then X is part of capitalism. My point is that every system can backslide into something more primitive where a strong man makes the rules.

I mean, that’s such a broad take, any system can change, doesn’t mean it’s inevitable. My point was that the core mechanism of capitalism, which is the private ownership of capital and means of production, will always concentrate wealth and power further and further.

We have had systems of feudalism and monarchies that have stayed steady for hundreds of years. In pre history, people lived in communes for thousands of years.

What is unique about capitalism is that it must move as fast as possible, hence why it can’t stay steady, thereby it changing to late stage is part of the design (as in you can’t have capitalism without it), whereas any other system does not, through its own mechanism, move towards some kind of endgame.