OK if you agree that these guys are stronger I'll begin to explain.
We all know that 1985 was an important year for D.C as it was the end of the Infinity Crisis and the beginning of Post Crisis Superman.
When Byrne took over Superman it was clear that he wanted to make a more realistic and interesting character. To do this he greatly depowered Superman. He was no longer the planet juggling, time traveling, Invincible God.
If you notice round about this time (E.g. From the 80's to before the 1990's), Thor Herc and Gladiator were performing similar cosmic feats. E.g.
Destroying Asteroids, Destroying Planets, Lifting the Midgard Serpent, Dragging Manhattan.
Yet since the early 90's Marvels characters have been enormously down graded.
E.G. Its now a struggle for Thor to hold up a Sky Scraper, Thanos needs the Mangog to cause havoc on a planetary level.
Marvels big hitters (E.G. Class 100 characters) rarely perform a feat greater than uprooting a tree or throwing a car. 🙁 🙁
Yet since those early Byrne days Superman, Wonder Woman and Capt Marvel have all displayed a variety of amazing Feats. Feats that only Ultimate Colossus has come any where near to replicating.
I know its not an official power down like D.C. but its definitely happened. I think it may have something to do with making the characters more realistic.
I mean take Neafria for example. In 99 he threw an Oil tanker at Iron man and then lifted a mountain sized rock. Both of these are impressive feats but they taxed his powers to the limit.
He has also shown that he is far above Thor in strength. If Thor had the cosmic level strength he once had, Nefaria would have easily been able to carry out these feats.
She hulk is another example of evidence to suggest that there has been a unofficial marvel power down.
Before her recent power up, she never showed evidence to suggest she could lift more than a couple of hundred tons. After doing a bit of weight training she is now supposed to be as strong as Herc (Who recently showed he is far stronger than Abomination).
The only way to realistically explain this is by saying that Herc was never massively stronger than her in the first place.
And even though Herc has been de powered, he still not that far behind Thor.
To summarise my point; All those Feats you use to suggest that Thor Etc are as strong as Supes are out of Date.
Superman on the other hand has shown many times that he can copy any feat performed by Count Nefaria and more.