Realitically it shouln't work like that but in fiction the super advanced society/being is always stagnant compared to the underdeveloped ones. The thing is i don't recall Galactus ever trying to improve or build more advanced tech. But i only have second hand info so i could be wrong. He just seems more worried about eating than building tech.
I think the tech is the means and the eating is the end.
The problem is as i said can't today can tomarrow. Simply because Galactus has the most advanced tech in the universe(save perhaps the celestials) doesn't mean it's beyond everyone to ever learn. Maybe beyond them today, but tomarrow who knows?
In fairness to your point Michael Korvac did steal some of G's power through technology. Although he had been augmented to superhuman levels but the augmentations were essentially of mortal design as best I can remember.
Korvac also deomstrated the ability, at least apparently, to use the Ultimate Nullifier from G's arsenal to destroy the Universe. G has never demonstrated the ability to use the UN to that potential that I am aware of. However, that was well after Korvac had absorbed the essences of several beings, the sum total of which likely far exceeded G.
So, in theory it might be possible for a natural genius to catch up to G's existing technology though it should take vast amounts of resources (time, etc.) to do so.
However, things remaining equal (time, etc.) I think you would agree with me that G's technology will always be vastly, if not infinitely, ahead of mortal technology?
I think that's the justification for the tech levels in the first place.
The fact that in the end he became the Supreme being should allow him even afterward to understand higher things than he previously has, and i don't see Galactus tech as his ceiling.
I think his experience as the Supreme Being probably imparted a deep wisdom akin to a stage of spiritual enlightment that wasn't there before.
I can't tell that this has had an effect on his tech however, maybe time will tell.
By the way, I am much more amenable to the notion of Thanos catching up to G's tech than Richards or Doom. Thanos is, after all, an augmented "Eternal" (Marvel terms, not IH).
He's probably two tiers behind currently, whereas Richards or Doom are more like 4 or 5 tiers behind.
If the writers want to make Galactus stronger than the LT it's thier business(these are the people who made Spiderman stronger than a herald of Galactus).
I certainly don't think that is what Starlin (who wrote that bit) intended. For all I can tell the LT didn't intervene because G's use of the Gems served a higher purpose.
But even the LT was below HotU Thanos.
Agreed, unless a retcon is forthcoming.
Somehow i can't imagine weilding infinite power and knowledge the same as using a gun.
The only point I was trying to make here was that just because you can use something (i.e. Reed threatening H with the UN) doesn't mean you understand all of its nuances or can even use it it its full potential.
Reed surely couldn't use the UN like G or Korvac could. Thanos grew progressively more powerful the longer he wielded the IG an HOTU as he better understood how to use them. That alone proves that he had much to learn even though he sensed their potential when others didn't.