"Listen, the same exact things were said about women, or Jews, any number of groups of people who were excluded, by whatever means, coercive or not, from opportunities of employment, in various societies in the industrial world."
And the reason why that was a bad thing isn't that it is just always wrong to say that skill is correlated with various attributes. Those things are wrong because skill isn't correlated with those things.
Leadership skill is correlated with age. The alternative is, as I said in another post, to say that as a young person, you are currently as skilled as you will ever be. You will never learn anything more. You will never get any better. You will never deserve a raise because you're bringing more value to the business. You are almost certainly not going to agree to this about yourself. Even if you do, I'm going to tell you right now that I think you're saying it just to be argumentative on the internet, and that you don't really believe it. Particularly the raise bit.
If everyone's getting better with experience, age can't help but be correlated with skill. It's a bit weaker mathematically, but in practice, it'll happen the other way too.
The reason we can even entertain the idea that experience doesn't matter is that there was a relatively recent event in which the environment changed so completely and quickly that a great deal of practical experience was rendered irrelevant. However, by "relatively recently", I mean, the mid-to-late 1990s, when we went from mainframes and "big iron" terminals to commodity computers and the web. Since then, there has been no similar sea change.
"you're never going to want to change that"
What I "want" is utterly irrelevant. I certainly do not want a world in which people celebrate failure to learn from experience. But that want is also irrelevant to what actually happens, seeing as there are still a lot of people working very hard to produce a cultural environment in which we studiously fail to learn from the past. (That's not a crack at you; I'm more taking a crack at modern academia there, which to my eye is to a large degree devoted to precisely that.)
I would advise you to lose the chip off your shoulder, try to learn from people who have already learned the hard way, and stop thinking you've got it all figured out, because ironically, if you do in fact want to displace the older fogies, it is precisely thinking that you've got it all figured out and that you don't need to listen nobody, nohow that will prevent you from doing that. The correct path is to A: listen to the people with experience B: think about it a lot C: think about it in your local context and then D: tweak it as appropriate for your local environment.
I would also advise you to carefully distinguish between people like me, who include step D, and those who don't. That D is all the difference. By no means would I expect advice from those who have gone before to apply 100% in a changing world. However, the world does not generally change discontinuously, nor does it change as much as the tech industry sometimes fancies itself changing. It's still going to apply 98%. That 2% can still be a big deal; it's the difference between Uber/Lyft and a conventional taxi company. But it's a lot easier to get there with the procedure I outlined in the previous paragraph than to try to reconstruct the entire knowledge base from scratch.
If, on the other hand, you want to start a business where you don't focus on customers because that's what your old fogie advisors told you to do, and you don't worry too much about revenue because that's what your old fogie advisors told you to do, and you don't worry about how you're going to get repeat customers because that's what your old fogie advisors told you to do, and you don't worry about complying with the local laws because "move fast and break things" is more important than listening to your old fogie advisors, and you don't ask anyone for advice on how to hire properly because it'll just be old fogie advice, etc. etc.... well... I did my part here. It's on you. One less "young person" to worry about upstaging me in the future, I guess.
Ironically to me personally, even as I write this, my wife and I are watching a relatively young person basically throw their financial future away, against the advice of all of their family and friends. In this case not because of an active rebellion against the old fogies, just someone not used to taking advice, and who takes the advice not to do something as a personal criticism, rather than an attempt to help them. It's not an HN-type of situation either. A tech startup may be a lottery ticket, but there is a chance of winning, and as long as you don't hang on to a failing business too hard, the worst case scenario isn't really all that bad; you made a living, you got a heck of a lot of great experience, and you can walk into any number of jobs or even perhaps another startup if you still impressed your investors even so. In this case, the best case scenario is that after 20 or so years of exceedingly hard work, they'll catch up to where they could have been if they just got a normal (non-tech) job, and both the average and worst case scenarios are substantially worse. Failing to learn from other's experience isn't just an academic problem. It's a real problem.