That's hardly the problem though. Kids generally love it when you tell them they can do anything, because most of them are absolutely terrified of the future. Beats saying "you'll have to go into your dad's business." And when your parents usually come home from work screaming and stressed out there isn't much of a rush to get there. TLP is a crazy man who forgot to take his lithium.
It's not about narrowing expectations, it's about helping them to understand themselves. Remember, the quote is "all you said..." We're in a time of immense cultural flux, and for many of us it's entirely unclear how we fit into the larger human picture or indeed whether we do at all. We've spent the last 30+ years blowing up the old order, but we forgot to replace it with anything.
Yeah, I suppose you are right. But I'm not sure if people ever had a clear sense of what they wanted to "do with their lives" or what "manhood" was supposed to mean. I mean, as a kid you could ask an adult but they'd usually just say "well I liked x job." I definitely agree with the culture shift though because fanaticism is through the roof and angry young dudes™ keep going crazy and shooting places up. There's an overall sense of doom and gloom even if you can pull a nice life together.