Past Era scaling

Open to hearing you guys view on the following topic . I strongly believe the shonen troupe of the previous generation being weaker than the current.

Can someone tell me on a factual Power scaling level why a Xebec of 40yrs ago and Kaido of 20yrs ago(Wano Takeover) + Oden are seen by fans to be stronger than what's actually shown. What I mean is this:

- Xebec absolutely has no feats and in my view on the Sengoku retelling I feel it's implied him being a terrorist made him the biggest enemy of the WG/Roger. We have to remember that Sengoku is naturally gonna speak from a WG/Winners write the history perspective. I also wanna say we have to remember Roger was sailing for Over 20+yrs on the sea before he reached his peak. I say that to say that to me implies he has a normal/average pirate growth rate and nothing like a Luffy, Zoro or Kobe type of growth rate where they can become insanely strong in days to months. We also don't know how Xebec got all those notorious pirates under him. Many think it was a Davy back fight but ultimately Oda hasn't told anything yet. Ultimately I believe Xebec was not pirate king lvl nor a Beginning of Series Yonko lvl in my opinion. I legitimately believe he would've been around a strong 1st commander lvl or maybe what some perceive as admiral lvl(above 1st commander but lower than original yonko)

Kaido of 20yrs ago(Wano takeover)- This Kaido to me has no great feats and is essentially used by people to scale Oden. His only true defeat was of Moria who yrs later a jinbe in marineford 1 shotted(nothing in the series shows younger characters become physically weaker overtime, in fact the opposite shows characters can not do nothing and get stronger till their 60's) . I say that to say I don't scale Moria as nothing special. He was his generation supernova and took a beating by their Luffy of the era. In my honest opinion I believe Kaido was around a current King Lvl. It's not a bad scaling especially when you remember King had the highest Durability on Wano naturally.I feel factually we have nothing to say Kaido was stronger at that time.

Oden- This is the most contentious. In my opinion Oden has no feats to put him on A Rayleigh lvl(who would've been at his prime) but probably closer to Scooper. I say the latter since the anime showed him fighting Scooper to a standstill and hanging out with him (which I take as the Directors showing he was more in league with him) Also gotta say Oden not having renown like a Rayleigh despite serving on both top crews of his era also to shows he's not on that lvl. He had a Luffy like personality meaning he was wild and wouldn't be low-key anywhere he went. Oda hasn't shown Oden to be worldy known like Rayleigh so i take that to mean there's a separation between the two in multiple ways. I also say the only factual thing we know is he was relative/superior to Kaido. And as I mentioned I feel was relative to Current King potentially. Folks also scale him off of Kaido top 5 CoC users. Kaido in my opinion was a fanboy of folks who personally either fought him or he encountered/respected and saw their haki 1st hand.I genuinely don't think he ever fought Garp in his journey and wouldn't even know that Garp was a Roger & Whitebeard tier. Saying that to say I don't take too much stock into that list. If folks look at what I'm saying I personally feel he was at King of Hell Zoro level . The only thing from feats that made him superior was being more skillful in using Emma and certain sword techniques(like cutting the mountain god). Which to me doesn't mean he's overall more powerful than that Zoro. Even if you believe Zoro to be weaker I still got them within the same tier of power