It's not rubbish. I don't talk rubbish Baden. The likelihood that a hatchie will "thrive" in a 4x2x2 is not great. The reasons they need close management when tiny are manyfold - hatchies need high humidity to shed properly on many occasions, and a poor shed on a tiny GTP is much more problematic than on tougher species., a tiny hatchie may get so distant from its heat source in a very large enclosure that it lacks the thermal mass to return to an appropriate site, to name just two.
The reasons GTPs are bred successfully in such numbers now is because the successful management of hatchlings in captivity has become fairly formulaic. There are exceptions, like there is with anything, but largely the code for successful GTP hatchling husbandry, especially for newcomers to the species, has been laid out very clearly by the likes of Greg Maxwell and the wonderful Rico Walder, who may just know a bit more about these things than you do. You speak of holdbacks - what age are these holdbacks? If they are 12 months +, go for it, but hatchlings from the past season... nah, it's very big risk.
It's been said, correctly, on many occasions that keepers cannot equate what happens in the "the wild" (where niche chioces are endless) with what happens in a artificial space we force our animals to live in. The best we can do is average out what we think is the best for the animals in our care.
Jamie