The beautiful thing about open markets, in theory if somebody can provide a more efficient exchange service, they will compete on local monero and drive the prices closer to market.

Classic arbitrage incentives, so if somebody else can convert monero to Roblox bucks very efficiently they could undercut current providers of Roblox bucks. We just need enough market depth to get those participants to compete. And until that happens the high margins are what incentivizes people to provide liquidity in obscure markets.