How i understand these miners developed long time ago and used by developers for mining cryptonight, and now he want sell him?
Miner developers (Baikal) use them while it is extra profitable, (why sell something, what make you extra high profit, without any competition, they mined quietly) and after they spoil the diff. and profitability start to fall, they start selling units.
Yup and this has been previously done by Bitmain and others, they "test mine" with their product for a couple of months typically before general public release. Just look at what happened on the SIA network, it was clear Bitmain had them running about 45 days before release if you look at the overall network hashrate.
These most recent miners are profitable, for the companies that produce them and the first few people that receive them. After that their value tanks.
Since Monero and I suspect other algos will are/will fork away from this Asic, it's long term value is highly questionable.
I wouldn't touch this device unless it could be had dirt cheap because of the risks of forks invalidating it.
The hashrate for SIA increased when bitmain shipped, not a day before. We were carefully monitoring it. See for example