I do not agree. In fact, I have been a 10x coder on occasion. The thing is not that I am extremely good, the thing is that I write very solid code that does not have to be thrown away after a short time or causes more problems than it solves. And I am not that much slower doing it than others are churning out trash. A better explanation would be that most coders are in fact 0.1x coders and should not have gotten into the profession in the first place due to lack of dedication, talent and skill. Then any good coder becomes an 1x coder and that is a far more accurate way of seeing things. An 1x coder in this sense is just somebody that delivers a solid result with good architecture, design and implementation in reasonable time. Most coders cannot do that.
I guess this "10x coder" nonsense comes basically from management being unable that they should never have hired the bad ones. Calling them 0.1x coders makes it amply clear who is responsible. Calling them 1x coders hides that management did screw up badly in hiring them.