First, I think it's important to clarify that there's a difference between being overprotected (and "kept away from life, other people, and reality") and from coming from a good home in which parents are capable, loving, nurturing, and skilled enough not to over-protect (and to instead somewhat limit some of what kids are exposed to while also helping them to learn how to process some of the difficult stuff as it comes along). Kids from the kind of "good home" I'm referring to don't live a cloistered life. Instead, they have parents who gradually encourage/allow them to expand their world and experiences, but with the aims of keeping some of what is "real life" or "reality" within some age-appropriate context.
Having a nurturing/"good" home is not always having "over-protective" parents, as many people tend to believe it is. One other thing to note is that while "having all basic needs met" tends to be an obvious one, children (all people) have a set of "higher needs" that aren't always obvious to people who don't understand what those "higher" needs are. Even the best, most loving, "good home", doesn't always manage to meet ALL the needs of a child.
One observation is that there is Maslow's "Hierarchy of Needs" (you've probably heard of it). It's the representation of psychologist Abraham Maslow's theory that before someone can go on to "working on" /accomplishing having higher needs met he must first have all his most basic human needs met. It's a pyramid, with things like physical safety, food and shelter at the bottom and "mental/emotional" needs higher up.
The appearance of having "all needs met" in a good home doesn't necessarily mean they've been met. In general, kids from loving, nurturing, homes tend to develop well. I'd compare childhood to involving a certain amount of "incubation" of an immature individual, with the gradual "decreasing of control of environment" as the child matures and is able to better cope with/understand the "realities of the outside world". The "great, big, world" is not a shock or surprise for children from truly good homes. Having been both sheltered (somewhat "incubated" until mature enough) and prepared for it, kids from good homes enter that outside world with an advantage that has nothing to do with material stuff or having unmet childhood needs.
There can be a downside and "strings" that limit what one will do to succeed; but I think inability to focus on goals isn't usually the real problem..