It has been done before as you said. I don't think 10k is something new, only that this time will be done by 3 or more guys in the same week.
And yes, a lot of fights needed and ironites to get to 10k. You can guess how much $ Jofer must've spent to achieve 11 Eternals in the pass!

Today I probably will get the 800 wins but still I will have less than the 1k wins from the time I got the Eternal.
The relics are a big advantage it's true, some fights don't last even a minute but I still have my ass kicked by players who aren't even 100level many times.