Illegal migration is a crime, and people who engage in it are putting their lives at risk. Furthermore, facilitating illegal migration is also unlawful and can have serious legal consequences. Therefore, attempting to profit from such activities is highly unethical and illegal. Also, the idea of sharing earnings 50/50 for such activities is not only unethical but can also result in severe legal and financial consequences.
People who choose such ways for migration risk their lives and are very much desperate to earn some money so that they can provide a livelihood for their loved ones. Can you imagine being in a situation in life where you prefer risking your life just to get a job or earn a living? They take such decisions because life is very hard for them, a lot harder than doing this.
But you are right, those migrating illegally and also those who help them do so are both basically vulnerable to legal consequences that they can face if caught in the act. Sometimes, they are even killed in the process if spotted by soldiers or etc. at borders.