What are the reasons for this?
The reason is easy, employees only receive a monthly salary, nothing more, for example the monthly salary is $1000, all the needs there are, according to the employee's monthly calculations, only $200 is left, the rest is spent on necessities, a situation like this is felt by almost all employees in this world.
Meanwhile, business owners have monthly/annual profits. If their turnover is large, of course their profits will also be large. Long story short, in one year the company owner will become a billionaire.
So, if you want to become a billionaire you have to be an entrepreneur/business owner, don't be an employee.