This is an argument for federative organizing for sure, although, kind of atypically for an anarchist I'm centralization-agnostic.

But in the land reform example, it says that after you do land reform, the peasants no longer have a reason to follow the vanguard because they can produce for themselves.

Imo this isn't an argument against vanguardism, it's just an argument for being careful about how you do land reform and the importance of setting up institutions of collective self management in the process.

Like, centralization can help us win, especially if we need to strike a coordinated blow. There's a reason anarchists of the early 20th century called for "one big union."

To draw on Graeber and Wengrow maybe central vs federal isn't as important as the flexibility to switch between the two as you need.