What was your "I can't believe THAT's still around" moment?

It might be on its last legs at this point.

Wow, it's still going? I got lost once The Casagrandes and (even moreso) those live action adaptations came out. I mean, it's not a surprise since it became a proto-Spongebob in ratings, but still. 
As a note, I happen to like a fair number of episodes from the earlier run, but stopped watching after 2018 or so when I was disconnected from cable, and only had Netflix for streaming.

I have been to the Cracker Barrel restaurant more than a few times in my life and to STILL see those giant racks of audiobooks and radio dramas is always pretty surprising to me. They've been there since my first trip to the place in 2001, and the rack doesn't seem to have decreased since then. The selection has changed up, but not the actual rack. Interesting.
On that note, while they are a miniscule fraction of what they were even in the 90s, radio dramas/drama CDs still have a market in Japan.

I had a moment last year where I was stunned to hear about a new, original Secret of Mana game coming out in 2024.

Sure, there was Trials of Mana in 2020, but that was a remake, not a new, original game in the series. We hadn't seen an honest-to-god new Mana game since like the DS era (outside of some Japan-only mobile games).

People I talk to in real life are sometimes surprised that Tumblr is still around and still has members after multiple acquisitions, selloffs, and purges (as well as the current AI "user data" fiasco, similar to what's happening over at Deviantart). Obviously, it ain't the 2008-2013 juggernaut anymore, and the site itself sadly has the feeling of hollowness of a lost "glory age" but it's still there.

Friday Night Funkin'

I personally remember going on there in 2013-14ish and I liked it a decent bit, even if I didn't get how the site worked. Definitely a lot more people there then. It's mostly a ghost town now. I think by 2018, nearly 1/3 of the entire userbase was reported gone?

I feel that Tumblr just didn't do enough to distinguish itself from other social media sites or even other art/hobby sites, and it didn't quite capture the glory days of fansites and fan forums. I imagine that it was just "another site" for a fair number of people, and I guess people moved on to other things once its popularity spike and place in pop culture faded. Now it feels more like a punchline than actual site.
I still use the site though, since my fansites and forums aren't ever coming back, and I don't like FB groups, or the format of Instagram for group discussions :/