The % of the network they would control would be too high maybe? Fundamentally the value of their product is based on the price of bitcoin. A single miner that gets close to 50% might be seen a a huge risk and drive down the price.
I’m not going to buy BTC (or whatever) from that system, therefore the owners take no cash from it. Yeah they have all the BTC, but so what?
Everyone loses. What am I missing?
I am speculating and don't know for sure.
Now I'm not actually sure if they produce enough for that to be relevant. But my understanding is they dominate the asic market and asics are the only thing that are profitable for mining bitcoin. It could be if they didn't sell and mined themselves they would have enough mining share to cause people to lose faith in the currency and crash the market.
Shorts? Conventional wisdom states that a 51% attack would destroy the very same value it would misappropriate, but when you can bet real money on BTC crumbling you get an entirely different playing field. Still very unlikely as everybody with that kind of hashrate is already rewarded far too handsomely, but if someone ever offers shorts on one of the smaller altcoins, I'd almost expect someone to state an at least cost-neutral attack just for kicks.
https://www.investopedia.com/news/who-jihan-wu-and-does-he-b...
Do you have any more recent numbers that tell a different story?