So Dong Tianyu didn't have a significant need for vehicles and therefore did not spend Contribution Points to exchange for them.
In fact, Dong Tianyu was very interested in the arduous return journey of Robinson William. Along the way, Robinson William actually encountered quite a number of serious crises.
Moreover, several of these crises, even just by Robinson William's recounting alone, could cause a chilling shudder to listeners Dong Tianyu and Madeline.
Because they were in the wilderness at the time, when the weather changed abruptly on several occasions, they decisively summoned their Companion Spiritual Treasure, which they originally rode on, so no matter how bad the weather was or how suddenly monsters appeared, they didn't cause too much harm.
Of course, there were disasters they could easily get through, as well as ones that nearly wiped out the whole group.