Nope, I think the idea is a bit different. Of course you can achieve this hashrate without immersion cooling. But you won't be able to keep it stable without good cooling system as ASICS would be overheated. That's why I think that their solution is good.
Not true, im running 18th/s for 6 month now and no issue. Of course climate here is around 20c all the time.
What firmware do you use to reach this results and what is the temprature on chips?