Having parents to fallback on is a great ruiner of motivation for some people. The amount of negligent enabling that takes place between some parents and their spawn is staggering. I think the extra assurance that they have the ability to live cheaply with their folks hamstrings childrens desire to establish their own support mechanisms.
The flip side is that when you don't have parents to fall back the risk level of all your actions become higher, and that will limit you in other ways.
For example, I emigrated in another country. Knowing that if I failed, I could go back home for a few months was a key factor ( as was the possibility to be there for a few months before, to manage the transition ). Maybe the extra-motivation of having my back against the wall would have pushed me in another successful adventure, but I would not have risked my career the way I did.
So well, that's really not black and white. And depends a lot on the type of parent you have.
Sadly psychological studies confirm this : there's nothing that motivates people quite like seeing a few others fail, and the consequences of that failure, like homelessness. This motivates a lot better than anything on Maslow's pyramid.
But would you really want to live in a world where this is actually implemented ? I wouldn't.
Your and my parents thought we wouldn't and didn't create such a world, even though they (or maybe their parents) did grow up in such a world, where failure to earn a living would effectively mean physical misery or even death (good luck trying to survive a winter homeless in Europe anywhere north of Italy). I say thanks for that. I mean I have a big fight with my parents but it's not about this.
