I agree that the example is rather idealized. I think the benefit of the Boots Theory is getting the idea in people's heads, encouraging them to think about how expenses and money can change with class. A difference in scale becomes a difference in kind, and it's easier to notice that when you've already got a simple example you can easily wrap your head around.

An excellent real round-world example would be a rent vs. mortgage. After 10 years, your typical renter has spent more on housing than they would have on a mortgage, and they're no closer to owning a home.