I graduated college in 2014, and since then I've been working continuously to buy games I missed and beat them. I've gone through massive buying spells which inflate my backlog, and periods where I'm powering through game after game. I've gone from 35ish games in my backlog in 2014, down to 7 in 2015, back up to 53 by early 2017, and right now I'm on a big downward trend where I've got just 10 games in my backlog. I'm hoping to keep it manageable from here on out, especially since I think I've "caught up" on most of the stuff I was interested in on older consoles.
I don't know if I'll ever hit 0, or if I ever even want to hit 0. It's about the journey and not the destination.
But I WILL finish Donkey Kong 64 some day. It's been sitting stubbornly in my backlog for 19 years, haha.