Legitimate is indeed the right word. You are correct on that. As for success, absolutely not. You do not have to be successful, you only have to be a contributor. How else?

Taxes are the means by which we empower the government to implement our collective wishes. Why should anybody, who do not contribute, have a say?

They can still have benefits, but they should not have ‘right’ to vote themselves into the goodies paid for by money taken from others by force.

Not understanding this principle is what led the entire Western civilization to the brink of bankruptcy. There is no limit to what people can ask for if they do not have o pay for it.