I can only speculate but $3 per card/day is a conservative estimate.
It's a good thing, monero devs will hard fork it, profitability will increase a bit again, cause right now only ethash is holding it and as many investors know there are possible eth asics mining already and they dont want to pay the current price cause they think they can buy it cheaper because of asics, reason eth is dipping every day x bitcoin and as soon eth devs do something about it, investors will start buying eth once again and profitability will increase again.