In as far as this is a document that says 'do your best, give 110% 25/8, sacrifice everything for the company', most of what I'm seeing here is the same general approval that latter-day HN gives all impractical advice that a very young person might come up with. ('Just do gooderer, all the time!')
I don't think the change is that people now are now closed-minded, I think it's more that something like Mr Beast's PDF of peppy twenty-something bromides simply wouldn't have made the front page at all in 2014. This would be over on Digg with the other pop-Internet stories.
More broadly, given that the comment section appears around 60-70% positive for Mr Beast, I'm unsure what it is you're actually after. Would you prefer it be 100% positive? Wouldn't that be a huge loss for the intellectual diversity that this site has to offer? Aren't there other, better places for hive takes (e.g. Reddit)?
Respectfully, I think the takes you're taking issue with are precisely the remnants of the old, diverse HN, and the takes you're tacitly encouraging are the monoculture that's taken over the rest of the Internet.