The normal projected benefit for this kind of social model is that people don't have to work for sustenance. Instead, the whole range of human motivation can become a driving force.
It is assumed that you get more focused, happier and more committed working people, because they can choose their work based on whatever motivation drives them. That could be money, curiosity, laziness, skill, chance etc. It is also assumed that people would be willing to take greater risks, since they can be sure they a) won't become homeless and b) won't starve.
If society provides a safety net for everyone, you don't have to build your own while trying to do all of the above work on top of creating a baseline of security.
Then the children of really rich people should really be an interesting lot, since they have all their needs met plus have plenty of money to do whatever they want, right?
Personally, all the people I know who inherited their money are useless and/or dysfunctional. I'm not saying that none find the motivation to do much with their lives after their needs are met... but to assume that enough of society is going to behave that way to change the way that society works seems to be wishful thinking.
Selection bias. You're specifically selecting for people whose only money is money they inherited; failures, in other words.
There's a lot of children of rich people who are quite successful in their own right. Bill Gates, for example, did not come from a poor home. And the other thing you have to watch out for is reversion to the mean. It's unlikely Gates' children will outdo him.
"Personally, all the people I know who inherited their money are useless and/or dysfunctional."
So you don't know a lot of people who inherit then. That is probably because most of those people do not show off this money and you will never know.
You only see those that show of and why not to say it? what you want to see based on your prejudices.
I have known a lot of people who inherited, some of them are useless or dysfunctional, some of them are really resourceful and know how to make good use of his money. E.g the creator of "Zara" inherit a small clothing store:
http://www.zara.com/
Now is one of the biggest in the world.
Half of the greatest philosophers, mathematicians, physicist of all time came from wealthy families, so they could dedicate time for non-primary necessities, a luxury even today.
Not a fair comparison. Children of really rich people are way more richer than the people living with only what is needed for "basic sustenance" (food/shelter/health).
It is assumed that you get more focused, happier and more committed working people, because they can choose their work based on whatever motivation drives them. That could be money, curiosity, laziness, skill, chance etc. It is also assumed that people would be willing to take greater risks, since they can be sure they a) won't become homeless and b) won't starve.
If society provides a safety net for everyone, you don't have to build your own while trying to do all of the above work on top of creating a baseline of security.