Salary earners end up spending their salary buying from the business owners making the business owners to get profit from the business while the salary earners end up with nothing.
Salary earners are just modern day slaves. They get a pittance for their work, because if they were to put the same amount of work into their own business, they would earn much more money.
Having said that, earning a salary is also far easier because you do not carry any kind of real responsibility on your shoulders, even if you make a mistake that costs the business a fortune, the worst you have to deal with is getting fired and having to find a new job.