It still exists!
What doesn't really exist is the excitement about the web as a publishing platform. Those of us who still write CSS for a living probably do so in the context of a webapp, a product that's trying to help a user accomplish a task. We usually work with other developers, and writing CSS like you do on CSS Zen Garden would probably get you fired. If you are an indie publisher maintaining your own website where you can actually control the CSS - get ready for spam, and hackers, and bitcoin miners, and people using your server as a launchpad to do illegal things and get you blamed for it!
Social media won, and it's social media like Facebook or TikTok or Reddit where you have zero control over presentation, not even social media like MySpace or LiveJournal where you could do cool things with CSS.
BTW I remember not being excited by csszengarden and I knew one guy being excited about it. I'm still not excited tbh, I miss flash and photoshop heavy websites.