there's just no point to all of it.
But we're committed to these games, for better or worse, and so the usual reaction isn't to just stop but to try doing something different. To go for a different approach, level a different character, take on a new set of challenges. And while it takes some time to hit that perfect combination of elements, there's something for most of us that usually reignites that spark that you had when you first started the game. It went from interesting to boring and then back to interesting again.
How do you get yourself back into a game that you're finding yourself more lukewarm toward? Do you play a class that's outside of your normal range? Try setting some arbitrary challenge for yourself? Go to areas you usually don't? What gives you back the energy to log in to the game?