Yes, I think tipping should definitely be encouraged. I can think of some systemic ways to encourage it, but not sure how well it would be received.
We should have had it all along and I can't imagine why it's taken so long as it's a natural fit for this platform. Now since it's just coming around after years of established different behavior it will take a while before the culture shifts to tipping becoming a normal part of how users use the platform.
Yes it will take a while to adjust behaviour. We've grown up upvoting for free and getting something back for it. Thank you for the tip :)