or they might buy a business and make enough parnasa that way
Just remember most small businesses fail, taking a lot of the founders cash with them. Running a company takes skills and real commitment. To buy a business you will need money (Where are you going to get it? Family? Bank Loan?) you will need a plan on how to run it so that it makes money and to work often very long hours. It can be done of course but don’t assume it will be easy.
A lot of young men are leaving Yeshiva with no idea of what will be required to support a family or even that they have no idea.
In the real world you will need to write proper English (Not yeshivish), be able to show up to work on time and get the job done or you won’t have one.