I've been thinking about how to respond to this for a while and here's what I have come up with -- I think the premise of your original question is "how the other half lives". Well, the fact of the matter is that people are pretty much the same at all income levels. There are some that leverage assets for the right reasons. There are those that use leverage to stretch for things they shouldn't be buying. And there are those that don't like debt at all. These groups exist at $1 of net worth and $100's of millions of net worth.
Similarly, there are those who are drawn to complex financial arrangements in order to maximize the value of whatever they are doing. At average income levels, these folks are maximizing credit card rewards. At the upper end, they are creating complex tax-efficient structures to buy and hold assets. And there are those who like to keep things simple and are willing to forgo the last 5-10% of value in a deal.
So, to your question about financing, I wouldn't finance a personal use turboprop. I also wouldn't take advantage of 0% financing on a new mattress. (Of course I might try to negotiate a discount for cash...
)
Hope this helps.