I haven’t really been convinced by it. There’s no archetype connecting the two, and most maid/heir models typically make maid passive and heir active, where I think canon suggests the opposite.
I found that assertion really interesting because the parallel he mentions is definitely there, even if it’s not necessarily the main thing about the classes. Mostly it boils down to an observed trend of Maids losing parts of themselves and being pressed into service by an outside force, be it the voices of ancestors, the will of the Condesce, or more vague societal pressures. Coupled with the fact that John (and to a lesser extent Equius) kind of has a lot of his power given to him in the form of an apparent outside force, and it’s not a hard conclusion to reach, doubly so with the immediate emotional associations of the words “Maid” and “Heir”. That I don’t agree with this conclusion mostly just boils down to, like, having a lot of other evidence pointing in other directions, like the fact that each class pair seems to share an overt archetype linking them, and there isn’t really such a one for Maid and Heir.
this is a better, more fleshed out answer than my initial one so here u go
Flying through Storytelling 