Similarly here, by putting all the transactions on-chain, you have to strive to find the best possible on-chain scaling technology, like thin blocks doing right now. But if you start to become lazy and try to use the old centralized financial models like payment channels because they can provide millions of transactions per second, then you just drag bitcoin into the old banking model, which will dramatically reduce its usage and increase its risk, especially when there are many other alt-coins provide on-chain scaling
I can't agree at all.
Payment channels are _nothing_ like old centralized financial models. Who is the trusted third party? No one.
When you go on and on about "on chain" you're confusing a technical mechanism for a social or business business goal. Everyone being able to transact with everyone else at low cost and without the risk of censorship or exposure to extraneous counterparty risk is a laudable goal. "On chain"-- meaning transacting in a lock-step synchronous world wide flooding network-- is a technical mechanism. On that, to the best of our current understanding _cannot_ deliver that business/social goal. Fortunately, we do know ways to deliver it.
It's like walking up to some aircraft engineers and demanding that the next design be exactly the same but have a wingspan twice as long, when really your goal was to double the number of pounds of cargo it could carry. Maybe the change lets it carry more cargo, or maybe it just makes the plane unstable. Regardless, a particular _mechanism_ was confused with the business goal, and as a result an end-run around the science and engineering that could, potentially, have actually met the goal if given a chance and allowed to make the required tradeoffs.
Of course, there is always someone out there that will tell you that you can solve any complex problem with this one weird trick. But there is a word for them: Scammers and their patsies. And right now, there is a whole clique of the Bitcoin old timers who were bamboozled by Craig Wright and his 419 scam which predominantly featured a ton of magical scalablity claims... it's going to take a while for their wide and greedy eyes to blink and realize they've been tricked, and that maybe these magical scaling claims were just as fraudulent as everything else.