That's not what I am seeing in practice. Currently on one server the Alpha has grinded something in the order of 5,000 boulders due to the two weeks of x2 as they haven't needed to build anything else since due to x2 now they are just reconfiguring their base for fun. When there is nothing left to do, you might as well stockpile for wiping and start pushing breeding to the limits.
My biggest issue, as I said is not the x2 harvesting however. Its the x2 XP and Taming which has made levels 1-60 completely irrelevant, and the fact that high end tames are now ridiculously simple to get. Im not worried about the egg tames, its more looking at things such as Gigas which the challenge is already gone for Alphas generally beyond the actual making of the kibble (due to people often times being lazy). Now the only challenge is knocking it out. For every Giga they/we used to be able to tame, now they can have two. And this again scales disproportionately. There is virtually no downside to now just going with having 150 Gigas functioning in your role of Rex's. They are cheap to get, and there is no way someone is breeding a better rex than you can have with any 130+ Giga. (unless you get an absurd stat distribution like everything, literally everything in Oxygen).
But that's getting off track as I already think the Giga is a bit too OP and not really an "end game" tame as it seemingly was intended to be. x2 just makes it even less so.