This is unduly negative. I've read and reviewed books by fellow authors and they've done the same for me - not as an exchange but because they wanted to. They often read mine first and it made me interested in what they were doing. Some people prefer to try self-published works and support independent authors. It's also perfectly possible to sell in big numbers with no budget. I have an acquaintance who's had a lot of success with his military memoirs.

Obviously you need to get a wider audience outside of your writerly circles, and yes marketing is hard, but this all applies when you have a traditional publishing deal too. I've made more money self-publishing than through any of my book deals with actual publishers.