Being at end-game does not make one not casual.
My partner and I both have a maxed level class and while we're working on our 'end-game' equipment we're taking our good sweet time doing it because we're also fooling around with other classes, with crafters and gatherers and with just being in the world with people.
Considering how incredibly easy it is to get to max level, and how incredibly easy it is to acquire tomestones if you want to it is very easy to play it casually and still be up there with the so-called 'hardcore.'