Because if all else fails you’ll find another job

Maybe your plan to work for yourself won’t pan out.

Maybe you’ll quit your job, start your business, find no customers, make a loss and run out of money.

Maybe you’ll have no choice but to look for another job in a few months or a few years.

Some employers will look at your resume and reckon those months or years as a mark against you. They won’t offer you a job. If they do, you shouldn’t take it.

Other employers will look at your resume and reckon those months or years as proof of your independence and initiative. They’ll fall over themselves to offer you a job.