I disagree.
Momonuske is just 8.
Grown up artifically by 20 years with zero training, he is hyped by both Luffy and Zoro for having a strong body. He also has Kaido's DF. Allow him ~5 years training with scabbards, and dude is at bare minimum getting to low top tier.
Scabbards may have looked weak, but that is because Kaido is too strong. Look at scabbards power level:
-
Kyoshiro: matched/overpowered pre Enma Zoro (he certainly looked better in the exchange). Strongest scabbard, Oda gave him the rare feat of slicing a ship (that he usually uses to hype swordsmen). Stronger than Jack, possibly ~ Queen
-
Shutenmaru: >= Jack
- Sulong
Cat/Dog: considering their base is relative to (but weaker than) Jack, their sulong forms are definitely at least Queen level.
-
Izo: stronger than all Toibiroppo/executives, defeated a CP0 agent in 1v2, where the CP0 agents mid diff'd Apoo + Drake + 2 numbers. Potentially low commander level similar to Jack/Cracker
-
Kin'emon/Kawamatsu/Kiku/Raizo: some Tobiroppo/executive level (likely on the higher end)
What we see here, are at least 4 standard commander level fighters, and at least 5 tobiroppo level fighters. All with advanced armament haki, meaning they hit hard relative to their tier.
This is essentially a Yonko crew without the Yonko and the first mate/RHM.
Scabbards collectively, would
destroy any version of the Strawhats pre rooftop. I wouldn't call them losers at all, they are amongst the strongest characters in the series.
The only reason they looked weak was because they were up against Kaido. They would've looked a hell lot better if they fought Big Mom instead.