Hardly years. Not even months. Merely doing the Alliance Roulette once per day should let you level from 60 to 70 in no more than a month. Adding in all the other ways of gaining XP, and you can easily gain one level or more per day.
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It's worth mentioning that something you shouldn't do is run the Leveling Roulette (or any roulettes) more than once a day as you only get the bonus once, not counting 'adventurer in need' status. If you do roulette without the bonus, you're just getting sent into dungeons that don't suit your level and thus give poor EXP. Queue for the specific highest-level dungeons instead.