What I find when reviewing projects or analyzing problems is that the young engineers often have serious trouble seeing what is under the surface. All those "frameworks" and tools are standing in their way and it becomes very hard to understand what is going on form them. This results in bad performance, huge bloat, insecurity and bad reliability.
What the IT field has really missed and the younger generation is suffering the effects, is that fundamentals are important and if you do not understand them, then your product will suck. Sure, if you want to push out crappy software fast, get some young morons that have high intelligence but no experience and actual insight. But if you want to get the cost of IT down by actually solving problems and having them stay solved, make sure a significant part of your engineers are experienced and knowledgeable. Yes, that means getting older folks into the teams. Don't get me wrong. Many older folks are just as incompetent. But experience can _only_ be gotten among older folks, as it takes time to acquire.