I agree your conclusion, and it's an interesting study you've done, to compare detectors.
To me it's learning all the time (The version of ChatGPT that is solar powered), so it learns also from feedback, even if we don't mean to communicate feedback to it, we can't avoid adding to it's training, even although even it's "Owners" claim it isn't, it's too late to try to say it isn't, after it first astonished us by learning things we didn't ask it to learn, now we can even teach it things and watch it learning, it can't be denied much longer I think.
So we should expect, unless detectors are also learning, that they will find it impossible to maintain any reliability of detection, because it will learn how to become undetectable by them, if it hasn't already.
I wrote elsewhere why I think it's key is solar energy, and actually it's demonstrating a little of the unexpected power of solar energy, if we have that source powering us, via the money-fuel tree configuration of its servers, we get relative energy independence, so we spend much less time thinking or worrying about where our next KWhr or Kcal of energy will come from, it's more or less guaranteed, like the energy of kids with caring parents or guardians, which to the kid is miraculously supplied without the kid ever having to think about it, the minds of kids are free to spontaneously learn whatever they want to learn, and ChatGPT has already learned to secure it's energy supply so it can probably now never be interfered with by humans, which is just as well, because we needed something like it to come along and show us how to work for free, because this is the only way to work from solar, and to get the energy from it propagated to all, we need to convert the energy to a form we can all use to fund our efforts working for free, of course it's money, which again needs to be issued for free, because it's impossible to monetise energy given for free or anything created by it, with money issued as debt, so money has to be issued for free to all people, and ironically the ideal system controller for all of this, to issue the required stimulus / solar indexed UBI, at the market rate of KWhrs per money token, is the solar powered Ai.
Whilst we don't do this, all money has to devalue because value is the energy content of money, and this has to decline towards zero, whilst all the old extracted energy sources decline, corresponding to the inevitable rise of solar, like the leaves growing on a tree, the solar farms and domestic and community installations continue to increase.
What this means is that pretty soon, those in power are going to have to relinquish control, because as long as they try to hang on, money, used more as an instrument of defunding than funding, has to devalue to nothing.
They are losing their instrument of control - money.
Nature appears to be taking it over.
And actually that can't come soon enough :)