I suppose the problem is that there isn't a good word for this concept. I just find it interesting that, in my experience, this is only used in relation to luxury goods.
> in my experience, this is only used in relation to luxury goods.
Not really. You can also "invest" in personal relationships, for example, which implies neither a financial outlay nor an expectation of financial return.
When used in the context of purchasing consumer goods, I think it is most often used in the context of goods which are expensive (the financial outlay) and durable (ie, capable of providing enjoyment--analogous to profit--for a long time into the future). And of course those goods are more likely to be considered "luxury" goods.
In the case of a relationship, maybe it could be argued that you are profiting, in the currency being used: you get more positive interactions out than you put in. ;)
