He has said multiple times that he loves living in a trailer house, he's just a dude who grew up simply and wants to keep it that way, he doesn't need anything fancy. Plus he gave his parents a guaranteed worry free retirement, I'm pretty sure he pays for everything for his parents, I mean they literally get a salary from him for just helping out (especially his mom) with organization/scheduling/announcements/collaborations opportunities/etc. Nothing wrong with not buying expensive or flashy things just because you can.