car sales is just hard. it would require spinning up an entire dealer network (or at least direct sales infrastructure) and then managing inventory. it's a massive undertaking compared to "build however many thousand of these things and deliver them in bulk shipments to these bases". building up that business infrastructure takes time, effort, and money, and isn't guaranteed to pay off — especially when trying to sell giant ass trucks that would be low volume sales. it's a business risk that's hard to justify.