I think there are two types of folks. In one camp you have those that retire early because they are wealthy and buy an RV to travel. On the other hand there is a segment that is normal folks who are sick of the rat race or got laid off and have enough money to retire if they live extremely frugally and living in an RV is a way to save money and forgo the expense of a house.
I imagine this Amazon thing is attractive to the latter type of situation.
I'm not sure I'll retire at 50, but I am sure I won't be working 60 hour weeks out of a van. Unless something changes dramatically, of course. You never know.