Okay, so I don't know how much of this came across in the English version, but the Japanese stream was clearly pushing a few points:
- The pre-match promo was filled with Naito quotes about how a star doesn't need a belt to shine and focused entirely on just main-eventing in the Dome. Okada's half meanwhile was all about "Great, you've got all the accolades and the fan support, but are you satisfied with just that?"
- Naito's got the fans on his side, but you need more than that to take the IWGP title in the Dome. Okada probably saw his past self in the current Naito, flashing back to when he had all the momentum in the world but still couldn't get the job done against Tanahashi. Naito also emphasised this by constantly playing to the crowd, trying twice to hit the Stardust Press etc.
- Naito's the older guy and the senior in the promotion, but Okada beat him to basically every possible achievement. He then turned around and asked Naito in his post-match promo, "So how'd you like being in the main event in the Dome? It felt amazing, right? Well, it feels even better when you win. Let's do this again sometime," which I think was supposed to come off as super condescending. But the rest of his promo was super babyface, so I don't know lol.
So basically Naito was so obsessed with main-eventing WK and making up for losing the crowd in the past that he lacked the hunger for the top prize. In his mind, this was a replacement for WK8, which is why he played to the crowd and why he wanted to hit the Stardust Press so badly. If he wants to beat Okada, he needs to have the desire and the sheer force of will to win and be champion.