Of course Bitmain is filling its datacenter with newer gear. You don't think they're just going to sell that new stuff to the general public before they get a chance to milk it themselves, do you?
. It's absurd that they are selling those secondhand S5s at new retail prices. What's even more absurd is that people are buying them. Talk about rolling in profits... let's mine with this gear (which we already charged our customers for their contracts) and now let's sell it again! Brilliant! Even if those S5s were not part of some hash rate contracts, they were still mining for Bitmain during the entire time. Just food for thought:
Retail price at launch was about $450.
Orders opened around Christmas, 2014 (or thereabouts).
Assuming today's difficulty, that S5 would have mined you 2.17
BTC from 1/12 until today. Obviously, the difficulty was lower in January, but since retrocalc is still FUBAR, and I don't want to write my own code to calculate it, I'm lazily putting that number up
.
Bitmain sells that S5 now for $400.
So, assuming it's been mining for the past 195 days (probably longer) and today's difficulty was constant that entire time (absolutely not true), and is sold to you today for $400, that single S5 has made Bitmain over $1000. Since my numbers are skewed to a higher difficulty, that S5 has actually made considerably more than this.
If I get motivated enough, I'll write my own code to calculate expected payouts between two dates given a hash rate. I wish retrocalc was working properly so I wouldn't have to.