Great idea @sumatranate!
I still see Steemians on the network that are making decent Steem rewards, and some of them are utilizing zero tribe tags! I make it a point to let users know when I see this, and some of them come on board, some of them don't. I won't over impose the idea, but I do hope that many of the "old school" steem cats will come to adopt tribes more willingly.
Oftentimes, I hear that people simply didn't know. Giving @steemtribes a follow, and will direct users to the account who I come across that want to find out more! 👍
As you said, I think a lot of it comes down to "I didn't know." People don't know what they don't know. Thanks for your interest in and support of @steemtribes. I hope SteemTribes.online will become an increasingly valuable resource.