I emailed that wonderful news to another friend who soon after replied that just five people control half the hash rate! (However I am unable to find a link just now.)
Electricity is real cheap in China because the Commies think it's cool to die of asthma: "Clean coal" as President-For-Life Trump explained it.
With a very small initial investment one can bootstrap a large mining operation by spending all of one's mining profits to buy new mining rigs. To some extent bootstrapping is required of every miner because the coins become more difficult to mint each time a new coin is minted.
Satoshi Nakamoto's original paper demonstrated that there is a hard limit of 21,000,000 bitcoins that can ever be minted. Since 2009 or so 16,000,000 have been created but that hard limit is not expected to be reached until a century from now.
Vancouver, Washington's electric power costs 8.16 cents per kilowatt-hour. CoinWarz' BitCoin Mining Profit Calculator [coinwarz.com] estimates that I'll profit about $11k in my first year; it should be a little more than that because I can turn down my heater during the winter.
It's not the S9's cost that was troubling me, but my concern that I won't tolerate the fan noise. My new rig is going to consume 1350 watts so I can turn off my apartment's heater, but without those to turbojet fans the S9 would melt into a puddle of molten aluminum.
What motivated my decision to buy an S9 anyway was Susan's Facebook post.
What sealed the deal was that other friend telling me that just five people control 50% of the hash rate