Are you saying there is an arbitrage opportunity there? I doubt it.

Wide spreads usually mean no arb opportunity.
Narrow spreads equals potential arbs.

The spreads are wide because no one is trading that pair. Which makes sense because it's just as easy to simply withdraw and send to the other side, as you've described. But why would you do this either? The other markets trading PPY are thin and have wide margins as well. There's no advantage.

Arbitrage doesn't bring spreads closer together. Market making does, which takes on risk. In fact, arbitrage always widens the spread because you're taking orders off the book not adding. The exception to this is a "copy-cat" type market maker which could potentially be characterized as a type of hybrid arbitrage.

I'd love to see more market makers like this. I used to run one myself. That would replicate the books of external exchanges onto the dex. It's somewhat problematic though and subject to manipulation given the 3 second delay on the DEX and near instant response elsewhere.

One last point regarding the PPY:openPPY spread. If I were arbing those markets(I am) I wouldn't care what the PPY:PPY spread was unless It was trading 1.01 PPY for 1 PPY which it never should. It's cheaper to withdraw. In and arb sequence if I buy openPPY and sell PPY. I'm not going to finish the circle by trading my new openPPY back to PPY because I know they are the same thing and I can always get the same for them by withdrawing. The only time you'd withdraw from one to the other is if you run out of supply on one side.

The same:same markets are mostly useless. Especially if you're dealing with a coin with 3 second confirmations. I can see the utility for transferring BTC or some other slow coin as you might want the other BTC more quickly than the withdrawal can offer.

Anyone making a same:same market will have to offer a spread less than the fee to withdraw or no one will use it.