Debunking Mihawk didn't grow any stronger after his fight with Shanks, by using Shanks as an example
There’s this argument about Mihawk that I keep seeing everywhere, and honestly, I don't get the logic behind it. People claim that Mihawk couldn't have gotten stronger just because he hasn't fought anyone on Shanks' level in 13 years. This logic is totally flawed and completely falls apart the moment you apply it to other characters. I’m going to use Kaido and Shanks himself as prime examples to prove why this argument is completely baseless. The assumption here is that fighting is the only way to grow stronger, and that if you aren't constantly fighting someone stronger than you or at least on your level, you can't improve. This is obviously completely wrong—there are other ways to grow.
First, let's look at Kaido. After his fight with Oden, he sat in Wano for 20 years. He barely moved and never fought a single powerful character who could push him past his limits to make him stronger. Logically, the version of Kaido that Oden fought was way weaker than his current version—proven by his current use of Advanced Haki and his Hybrid form. It makes zero sense to say Kaido stayed at the same power level for 20 years. So the question is: how did Kaido grow stronger?
His fights with the Marines happened even before he joined the Rocks Pirates. And if you want to bring up Moria, let's be real—Moria wasn't strong enough to push Kaido past his limits.
The second example is Shanks, and he is the ultimate proof of how flawed this logic is. If we look at the feats Shanks fans always hype up—like his fight with Loki or his clashes with Whitebeard and Kaido—let’s break them down from the start.
Take his fight with Loki: if Shanks fought Loki, defeated him, and tied him up, doesn't that mean Shanks was already stronger than Loki before the fight even started? How else could he beat him? I don't get why people act like Shanks defeating Loki means he only got stronger because of that fight. Shanks had to be stronger than Loki before they crossed paths. So, how did Shanks get that strong in the first place? To our knowledge, the last powerful person he fought was Mihawk. The only logical explanation is that he grew stronger through training and honing his Haki, just like everyone else.
As for his clashes with Kaido and Whitebeard, that’s even bigger proof. If Shanks clashed with them, it means they were either equal in power, or Shanks was stronger. If Shanks were weaker, he would’ve lost the clash outright. So the same question applies: how did Shanks get that strong when he hadn't fought a top-tier since Mihawk? Every single character he faced—whether it's Loki, Whitebeard, or Kaido—Shanks was either already equal to them or completely surpassed them before the battle even began.