How Japan Is So Variant, Right?

I never understood that about Japan being such a tiny island country. And yet having even dialects be so different throughout all of Japan. How is that possible? Like how did we stay so separated in all of our like clans, so to speak?Like the UK, right? Yeah. Are you guys similar? Well, I guess so actually. I guess like 20 different accents just in London. If you drive 10 minutes, it's totally different accents sometimes. It takes longer to get to the opposite side of Shizoka than it does to go to Tokyo. So for like over 2, 3,000 years, each place was just like a different country. They just blows my mind