I have to ask, why do the readers(which the authors try to appeal to) find the old Dragon Ball Z formula so attractive. The old my number is bigger than your number. But the fights don't change in any way or the displayed feats. Nor it's effects on the surroundings.
Because it's about bursting through limits, and people like that.
^this
But at same time, you basically said the answer in your question.
"NUMBER GOES UP BOOYAH !"'s Human psychology. And Vampire survivor being one big example.
https://www.reddit.com/r/Asmongold/comments/1daddue
(oops wrong one)
(couldnt find the reddit post so i gave up and gave tiktok link found by googling)
It's literally just a never ending power fantasy. That's it. That's why people find it attractive. It would do poorly if it was released nowadays.
You basically said what said one of my fav CN author in a author note rant.

"If it was released nowadays, it would do poorly"
(one of their "classic work" in their country's childhood, had a martial artist girl, being raped when her body couldnt move / she misunderstood at that time it was MC as the person put a napkin on her face)
Today there are lot of novels (or art) rivaling or surpassing the quality of old works, but bc of "abundance" they wont make as big a splash as them. Some succeed, some will fail and be incognito.

Crab eaters effect.

Slave harem series, Vtuber agency, TrueEndgame. Beside the first one with the arrogant author being rude against own "poor readers" (like a OF creator) and bad quality with lot of complaints, somehow became NUMBER1-SH-series for a long while.
The other 2 SH series (unlike first one) had VERY HIGH QUALITY but at same time, they were lucky to surf the wave of SH's start, Vtuber, AI be a interesting topic, and during the small period before GENz came and internet didnt have so much toxicity (pre-Endgame-marvel era). A era where people still commented a lot.
Its like art.

Danbooru. Years ago. It was full of medium quality. And people took the time to appreciate the good ones.
Basically same with "gaming".
Now there are so much of everything, that things that could be acclaimed before bc of how well it is, is now have like no popularity.
In short its like humans throwing the food away bc their table is overfilled.
Humans are weird creatures.
