@gvwilson Grammar is arbitrary and has never been optimized, is my guess. In Esperanto it's almost right:
I remain mi restos
you remain vi restas
she remains li restas
they remain ili restas
but then they get weird about plural nouns and adjectives.
@gvwilson old english strong nouns, masculine gender, had -as suffix in plural, so: sg. *dūd, pl. *dūdas — whence modern english -s, -es plural suffixes.
and strong verb bīdan, third person sg. bīdeð, pl. bīdað — the -ð in singular carried through to modern english -s in third person singular verbs, but the plural form dropped it.
so in old english you get your wish in the plural:
se dūd abīdeð (the dude abides)
þa dūdas abīdað (the dudes abide)
@gvwilson I abide, you abide, he/she/it abides, we abide, you abide, they abide
The odd one out is third person singular, not singular vs plural