Thats not Bitmain`s work, Bitmain was not fast enough this time. That hashrate is all Baikal`s work, they have been using(and producing) their machines since december and sold them once information about Monero`s fork became available.
Yah I think 3 or 4 companies have came out with Cryptonight asic miners. The ironic thing is that these forks will actually drive companies like bitmain to make the miners and never sell them to the public, thus causing real centralization. Most of the people who complain are those who spent a lot on GPUs and refuse to adapt to the future.
we needed to flush them out idiot, now we know what the normal hash rate for monero should be around 500 gh
if we see big jumps in succession we will fork thier doorstops again rinse repeat until they stop makikg asics
for those resistant coins and make fpgas which cost way more and can never as powerful
the battle has been joined and we will not fold just watch