In my experience, which may or may not be representative of the general case, bootstrapped and profitable startups with no funding often don't offer equity at all to employees.
Those are what I meant when I mentioned founders' savings, and I agree that they are risky:
> there are some startups funded by the founders' own savings or mortgages, which is a big risk
EDIT: Sorry, I now realize you meant startups that grow from their own income (or am I still misunderstanding?). Those don't seem very risky to me, since there's not much high gains/high losses potential to them.