The end game is similar to others in that it's a continual escalation - of time, not skill. Enough time and you memorise each boss pattern. Repeat what you have memorised with other similar players, then move on to the next memorising exercise.
Other games are very similar - apart from one major difference at the moment - they have learnt that funnelling the playerbase down one track is a recipe for a quickly reducing subscription number.
Their response has been a wide variety of content at lvl cap. ARR is only new and doesn't have that yet. But that's not the other games' fault and it's these others that are the direct competition.
Until ARR does widen the content players like the OP will continue to feel stonewalled