Thats what a did and came to around 2000 lvl80s at prime time (was like 1 year ago tho)
20 thousand subs , total player base of 80k ? That still sounds very utopistic , just play the game and you can see that this can't be anywhere close to reality
And since you always refer to steam spy , 80-90 players at peak time ? Really , that should give you to think about your numbers , especially since aoc has got its last boost after becoming available on steam.
From my eexperience most people do have a sub , because the F2p model blows . It might be different for new- and role-players . But everyone who wants to play the game properly with dungeons / raids just HAS to sub .