I think you should stay. Never put all your eggs in one basket. But be clear on what your goals are, and what your PRIMARY site is - you own and control that.

In my opinion, you need to be providing value here (you are), but also using this as a way to drive traffic to your main site. It's not a competition! This one can help support you and promote you on the other. (My first goal for Medium was to "earn my $5/mo. membership fee" and my second was to "earn my $5/mo. membership fee PLUS enough to cover hosting fees on my personal website." I have succeeded in this. It is not a "full time writing income" and never will be - it's not focused enough and I'm not pumping enough "content" into it on a daily basis. (Why would I, when I don't even do that on my own site? And what kind of machine would I be, if I could do it on more than one site?)

Medium is great for networking and supplementing your other goals. It is not YOUR #1 goal, though. Be clear on that.