What's your average earnings in BTC per GPU last year?
What is your prediction for upcoming year?
The only true answer is "it depended".
My rigs that were already built up and running at the start of the year probably ALL earned more then the cost of the rig by now.
My rigs that I've built up DURING this year, some were early enough in the year they are probably ALSO paid for, the ones I've built in the last 2-3 months have a ways to go.
I do NOT figure we are going to see RX 470 cards making $10/day again ever - but I can't say it's IMPOSSIBLE, just very very unlikely.
The only reason they DID do so for a short while was the HUGE SPIKE in altcoin pricing around March timeframe didn't give miners enough time to build rigs up fast enough to match that spike with a hashrate spike - but it took a 10X AND MORE jump in ballpark a month to get to that point.