"写书这个职业让赛马看起来像一个坚固稳定的生意"

Simplified Meaning:

Writing books is very unpredictable and risky, even more so than betting on horse races. Imagine you are placing bets at a horse race; you can win big or lose everything very quickly. Writing books is kind of the same; you might work really hard on a book for years, but there’s no guarantee it will sell well or be liked by readers. For example, a new writer might spend a lot of time and effort finishing their first novel, but the book might not sell many copies, leaving the writer with little money. On the other hand, in horse racing, even though it is also risky, there are some ways to guess which horse might win, such as looking at the horse's past performance. So, while both writing books and betting on horses are uncertain, writing books can feel even more unpredictable because there's less control over the outcome. To apply this idea in your life, if you’re thinking of becoming a writer, be prepared for ups and downs and understand that success might take time. It’s important to be patient and keep trying, even if the results are not immediate.