Being self employed doesnt automatically means that we would really be having that job forever which there's still a certain risk that you might able to lose that job and if you dont make yourself other

back up investment or businesses then your fucked since there are no other source of income you do have unless if you do get some job directly after you've been fired or laid off.

There's no assurance or guarantees on this world even on dealing with those typical things.This is why it would be more wise and sensible if you do always set out Plan B or Plan C and so on....