I miss it too! It was what got me going a lot. I have a habit of falling into an editing black paralysis where I'll edit, then edit, then edit, and never move on. Doing NaNoWriMo broke me of that habit and got me moving forward.
I won once myself, though I've never thought of putting that work on here. It's a super niche style murder mystery and I don't think that it would work. Though my secondary work I have on here came from an idea I had during one year's attempt.
I miss having all the encouragment and seeing so many people piling up their word counts was motivation!
Truthfully I even got the writing program I use, Scrivener, from their promotion on NaNoWriMo back in the day.