Because it sold out in 4 hours from their mailing-list-only announcement. So from a purely supply and demand perspective, it seems they could have gone higher.

Or maybe just a little higher. Their mailing list is comprised of the people most likely to buy this sort of thing. Selling to the general public might not result in many more sales than the mailing list alone, especially considering that the purpose/use of Urbit is so opaque.

Quite possible. Personally my decision to buy was based on a desire to finance the development of an interesting new operating system and p2p network -- so I paid cash to a company that is doing that -- so the purpose was clear from that angle.

Is there a verifiable record of which real-world entities bought in? It would be nice to have a way to rule out the possibility that they sold it to themselves to create the perception of demand.

In new schemes, you sell 10%, but claim you sold 100% in 4 hours so that you can start a new sale due to the "high demand" and try to really sell with fakely boosted "interested" abusing the greedy human nature.

Based on the paucity of information I gather was collected in the purchase process, I doubt Tlön itself could produce such a record.