Exactly this. I used to browse Reddit everyday, using one of these third-party apps (the official app and website being close to unusable).
When that app shut down, it just felt natural to leave Reddit behind.
I opened an account on Twitter instead, having never used it before.
The leadership of Reddit always seem to have been hated by the users, but I feel this might be the final straw that sends it the way of Digg etc.