Solana 150ms world wide finality time, centralization vectors

I'm not allowed to post in the Solana subreddit because I've asked too many questions and I'm trying to understand how this would work as it can be extended to Ethereum L2 as well. I actually do appreciate some of the technical advancements Solana has made, I just personally think Solana is way more centralized than people realize and it should become an Ethereum L2 to properly guarantee property rights and give users the option to exit to a credibly neutral L1 chain like Ethereum. Anyway, I was listening to Anatoly at the All In Summit and he was mentioning Solana's goal is to achieve 150ms finality time, specifically using Starlink. I was looking at world wide ping times and they're closer to 250ms (though I understand that Starlink can be closer to 150ms because of low Earth orbit).

What I am trying to understand, whether it's Solana or even an Ethereum L2, is it even possible to achieve 150ms global finality if you can't even communicate across the world that quickly? Even if you just used Starlink, which is a massive centralization choke point as you wouldn't be able to achieve 150ms through traditional fiber, and restricted yourself to top tier datacenters which is another choke point, is this even possible? I don't understand how you synchronize the ledger that quickly without introducing other issues, arbitrage opportunities, and massive centralization risks.