Early 20s and at least partial owner of an integrator, here. When I think of the "old" security industry, pre-IT, the words that come to mind are ones such as "slow" and "stagnant". I was trained as I imagine many were, through in-field experience with some mentorship from the older techs, and that especially fell very solidly into the "slow" category. This is only my limited, local experience, but I doubt anyone would argue that IT isn't one of the most fast-moving fields in existence, and that anything that gets mixed up with it will be dragged along for the ride whether the incumbents like it or not.
There are two big components to that, in my mind. The first is that the scaffolding/infrastructure/lower layers are already well-developed and standardized in IT, helping to prevent vendor lock-in and making it so that companies are competing only on the higher layers, where they can actually innovate and add value. The second is education. As with many specialty trades, there's not much in the way of support from institutionalized education. Personally, I didn't even know that this was a career choice. It wasn't even on the table for me coming out of high school. This is why companies that actively seek talent, and support their employees with continued education, certs, etc., end up being so successful. The reason people in their 30s are still seen as "young" is because that's how freaking slow the training/mentorship method standard at so many companies is. What's the youngest master electrician you know of?
All that aside, I have to disagree with your desire for the "old boys" to retire. Except in those cases like Integrator 2's where people are getting positions based on anything other than merit, those people earned their positions. I personally work with many who would fall into the "old exec" category that can still not only hold their own with me, but who have on more than one occasion prevented or fixed a mistake I made due to inexperience. They have their own strengths, I have mine, and we work together for a common goal rather than cutting each other down for being an "old boy" or a "young whippersnapper".
And most of all, nothing is "fair" if your idea of "fair" is anything except "you get what you earn", nor should it be. I still believe in exceptionalism and meritocracy.