WHAT ACTUALLY HAPPENS INSTEAD
The workarounds are the market, and they are all worse.
People are not naive about this. They have built a set of habits around the problem, and each habit costs something that nobody counts.
Meeting in person
Free, safe, and it means a seller in Surabaya cannot sell to a buyer in Medan. The item's market is whoever can travel.
Marketplace escrow
Works, takes a percentage of every sale, and only exists inside one platform's walls for items that platform lists.
Reputation scores
Useful for repeat sellers, useless for the person selling one camera once, which is most of these sales.
Paying by instalment
Doubles the transfers and leaves both sides exposed on the second half. Common, and nobody likes it.
Just not selling
The quiet outcome. The item stays in a drawer because the sale is not worth the risk or the Saturday.
None of these is irrational. They are all sensible responses to the fact that one person has to move first.