This man hosts Steinbeck for dinner in his mobile home, and he gives voice to the argument for mobile homes and how they fit into American life. When Steinbeck asks if the transient lifestyle bugs him at all, the man replies, "Who's got permanence? Factory closes down, you move on. Good times and things opening up, you move on where it's better. You got roots you sit and starve. You take the pioneers in the history books. They were movers" (2.5.31).
Basically, the argument is that, with economic problems and the like, it makes sense to be able to move where the work is—so a mobile home is totally convenient. And it kind of fits into, and harkens back to, the whole American pioneer tradition. Can't get better than that, right?