Shocked, shocked I tell you!
That is like a car company offering a stereo as standard equipment on every car instead of allowing you to choose which one you want and having it custom installed. Or including wheels and tires (tyres?) with every car.
That is like Apple or Dell or HP including an operating system in the price of their computers, destroying the market for 3rd party operating systems. Companies like Ubuntu would have to just give their stuff away for free.
Or including a web browser with every operating system; if they did that, it would just destroy Netscape as a viable business.
That is, it is business as usual. There's no crying in baseball. Sorry about your investment. And, by the way, if Amazon copied and released your stuff in two weeks after you did, you had nothing so original to begin with; you as likely copied them.
It's fine for El Reg to report the discontent, and not a bad article. But if this is the first time this occurred to you, do not be investing large sums of your own money in this sector.