I'm a parent. I don't even know what teaching reality means. Reality is more of of a function of world view than anything. Growing up in a fearful, hateful small town in bumfuck midwest is one world view. Growing up in the heart of Portland in the midst of racial riots and a pandemic another. "Reality" is more of a function of where you live and how you perceive things and how you are taught to react to it. The "reality" of trying to parent right now a fucking nightmare. That's about as much as I can say. If no one died, went to jail or ended up in a ball of tears crying some days I'll count that as a success.
One thing I'll definitely agree is learning how to deal with failure. That's definitely a problem and it's pervasive across all generations. I'm GenX. We just burry our heads in a bottle for our problems. Boomers, the generation ahead of me just never admit failure and pretend it doesn't exist. Generations younger than me were never allowed grace in their failure and are expected to be perfect and given the opportunity to grow when they did fuck up. It's a systemic issue that is very human. Look at Russia right now. They can't even call what they are doing to Ukraine a war for fucks sake. How do you expect anyone to have a centered base of reality in that situation?
I am also genX, 52 years old. I have 3 children ranging from age 22 to 30 now. You don't have to live a specific place to teach your kids about reality and real life. I will give you 2 personal examples out of many.. oddly both have to do with my x wife. She is of the "lets shield them from reality" kind of parent.. We clashed often (no, that isn't why we are divorced.. there isn't enough time in the day to get into that conversation). Example 1: We where driving down the road, and came across an accident, wasn't a pretty sight, one person died.. She told the kids to look away.. I told them no.. take a long hard look so yo know what happens when you are doing stupid things and not driving safety.. She got mad, we argued, and she said they will have nightmares.. I said good. let them have nightmares for a couple weeks.. I would rather they have nightmares for a while and remember this, rather than be shielded and do something stupid one day. It will be in their minds for ever and a reminder of why you always drive safely. Guess what, my kids are alert, and drive safety, none of my kids that I know of have yet to have a ticket, or an accident.. (well, that isn't fully true, my daughter was t-boned by a person who flew out of a parking lot and didn't even look to see if anyone was coming).
The next example is similar, but it was the news.. can't remember what it was, but it was very vivid gruesome coverage (I think it was a war or conflict.. but not 100% sure) . She told them to go to their rooms, she didn't want them to see it. I said no, you watch this, you need to see what happens in the real world.. what guns/war can "really do" to people. (they are avid gamers, specially the youngest who is into first person shooters, CS, CSGO, Call of duty, etc). Same argument as above. I don't see such things as something to shy away from, I see them as teaching moments... The problem is, most parents avoid such issues and conflicts.. Which means they avoid teaching their children about reality and real life.
The war in Ukraine with Russia is reality, it's real life, and the world History is full of such examples. It doesn't matter if Russia can't call it a war.. it's a war. But it's another lesson in reality where a parent can chose to educate their children (even those that are in the middle of it), no matter what Russia's stance is on it. The world is full of dictators and manipulators who won't admit truth. That is a reality and real life that we must teach our kids. To not do so is shielding them and lying to them about the world.
As for some of your other points, it all comes down to holding kids accountable for their actions.. but our society has developed into a society that doesn't really hold most people accountable, in fact it's become a society of placing blame on someone else, and avoiding taking responsibility for your actions..
Of course this is just my opinion and how I see it. I don't believe that is has anything to do with the brain development of 18 year old's. IF it did, we would have been having such issues decades or even centuries ago with nearly all 18 year old's. But it's only been the last couple decades that it's been 18 year old's shooting up schools.