No, 1 is 1 more than 0. There’s a certain sense in which you could say that 1 is infinitely greater than 0, but only in an abstract, unquantifiable way. In this case, it doesn’t make sense to say you’re “infinitely more productive” because you’re producing something rather than nothing.
It goes like this:
"For any positive "x", is 1 x times greater than 0? Well, 0 times x is lower than 1, and 1 divided by x is larger than 0."
So his productivity increased by more than twice, more than ten times, more than a billion times, more than a googol times, more than Rayo's number. The only mathematically useful way to quantify it is to say his productivity is infinitely larger. Unless you want to settle for "can't be compared", which is less informative.
I just read it as a turn of phrase that says exactly that, that it means they produce something rather than nothing.
I think it's a pedantic point, but maybe they just meant that talking about 1 being multitudes greater than 0 implies multiplication. And since 1/0 is undefined that doesn't make much sense.
Or otherwise, can you share what you think the ratio is?