With a 100% ROI already I see no reason why you should stop mining despite giving out some of your gpus out, maybe for the fun and experience try mining another coin besides ethereum...who knows you might just hit the jackpot.
Instead of scaling down , scale up and give yourself another challenge, I know you won't resist this challenge!
If you earned back all your mining equipment value less electricity fees then perhaps it can be profitable to continue mining if you have low electricity rates. The question being posed, or which should be posed rather, is what is the MOST profitable course. Of course nobody can predict the future with certainty so it comes down to a risk vs gain analysis.
Does the small gain earned while mining on a card outweigh the depreciation on a card? If the crypto market takes off again card values will soar and you will have made profit from both mining and also reselling your card at a later time. If it doesn't take off then the $0.30 earned on a 1060 doesn't offset the $0.40 depreciation.
Looking at the charts I feel the sentiment is still bullish for the time being with short activity still putting downward pressure.