The problem with passive income is someone else will be prepared to do the same (i.e. not much!) for very little money. The market is likely to eventually pric

The problem with passive income is someone else will be prepared to do the same (i.e. not much!) for very little money. The market is likely to eventually price stuff that requires no effort to make, very cheaply. You may be able to get quite a lot of money out of it before that happens, depending on how brilliant your idea is.