We buy things because it is easier to buy things than ask for things.
As children, we have to ask for everything we want (or even need).
When we grow up, start making money, we find out that we don’t have to ask for anything anymore, because we can always buy what we want.
Over time, we become so used to buying everything we want that we forget how to ask for anything.
For instance, for more than seven years now, I haven’t really asked anyone for anything, without offering an immediate or delayed quid pro quo.