It was speculated that Trump rally attendees were stranded in the desert because Trump did not pay the bus company. This article suggests that the drivers feared going back. The bus company pulled all drivers away from the event in response to what was see as an unsafe environment.
Trump has a well-documented history of not paying businesses and contractors, dating back to his time as a real estate developer. Many small businesses have reported financial losses due to Trump’s refusal to honor contracts or payments. This behavior has followed him into politics, where he continues to leave bills unpaid.