And how often did Blizzard add new things to do in content patches that were completely free? A new instance here, a new quest chain there, a new item set, whatever?
I have absolutely no clue. I don't play WoW. SoE does that next to never with its games. They do anniversary content which is in game briefly once a year, but the amount varies considerably from year to year. They also do some holiday content, but again that varies from year to year and is only up small portions of the year.
I repeat though, Everquest and especially WoW have much higher subscriber numbers and thus revenue streams than STO. That means a much larger budget for everything. They benefit from economies of scale.