Back in 2007, Netflix wasn't a globally available streaming service and they were still sending out DVDs.
> would not have looked twice at Kaiji
I still wouldn't, it's a cartoon, I'm not into cartoons.
> it first had to be publicly announced as 'popular'
I didn't figure out it was popular until after I finished watching the show. Meanwhile, while watching the show, I was telling all my friends about how much I liked it and recommended it to them.
Your comment reeks of "I have superior taste and people who watch Squid Game are sheep". Just accept that some people might just really like this show while not being interested in the Manga you enjoy.